Since President Trump began his second term in January, no high-level officials from the United States have met with their counterparts in China, even as the world’s two largest economies have taken turns imposing steep tariffs on each other.

In the absence of official meetings, Senator Steve Daines of Montana has cast himself as a go-between. Mr. Daines met with Vice Premier He Lifeng, who oversees many economic issues for China, on Saturday and was set to meet Premier Li Qiang, the country’s second-highest official, on Sunday.

In an interview with The New York Times on Saturday after the meeting with Mr. He, Mr. Daines, a Republican member of the Senate Foreign Relations Committee, said he urged China to take effective action to halt the export of chemical precursors for fentanyl.

“I met with President Trump a few days before I came over, and he was pleased that I was coming to communicate his ‘America First’ message and, importantly, to make sure that Chinese leaders knew the seriousness of the fentanyl issue, and the role that China can play in stopping the shipment of precursors to the Mexican cartels,” Mr. Daines said.

Chinese officials have said that the fentanyl crisis is rooted in an American failure to curb demand for the drug, and that Beijing has taken effective measures to limit shipments of fentanyl and its chemical precursors. China’s cabinet issued a report earlier this month on its fentanyl measures, and Mr. Daines said this was being studied by American officials.

Mr. Daines said he was trying to lay the groundwork for a meeting between President Trump and Xi Jinping, China’s top leader. “This visit is the first step to arrange and set up the next step, which will be a very important meeting between President Xi and President Trump — when that occurs, I don’t know, where it occurs, I don’t know.”

The White House has not named Mr. Daines as acting on its behalf. But Mr. Daines is one of Mr. Trump’s top allies in Congress. He was the first member of the Republican leadership in the Senate to endorse Mr. Trump in 2023 for a second term at a time when many Republican senators were leery of seeing Mr. Trump return to the White House.

“Given Senator Daines’s relationship to Donald Trump, China certainly wants to learn from him about Trump’s China policy intentions — whether he still wants to make a deal with China, and if so, what the deal would look like,” said Wu Xinbo, dean of the Institute of International Studies at Fudan University in Shanghai.

China also wants Senator Daines to “bring a message to Donald Trump that China wants to sit down to talk with the U.S. side and to avoid further escalation of the tensions,” Mr. Wu said.

Mr. Trump has imposed 20 percent tariffs on goods from China and threatened more. China wants to head off further tariffs.

“There’s a window of opportunity before early April for China and the U.S. to engage each other, and Senator Daines’s visit could play a pivotal role,” Mr. Wu said.

Mr. Daines said that he was not focusing on tariffs with China, because the Office of the United States Trade Representative has not yet finished a policy review.

Mr. Trump has said he plans to meet with Mr. Xi, without specifying details. China has said nothing publicly about a meeting. But the contacts between working-level administration officials that typically precede such a meeting have been absent so far during Mr. Trump’s second term.

Mr. Xi makes all important decisions in China, particularly on foreign policy. That makes summits with American presidents particularly important in setting the trajectory of bilateral relations. The two leaders met in 2017 when Mr. Xi went to Mar-a-Lago, in Florida, and Mr. Trump went to China.

The lack of engagement with Washington until now has led some in Beijing to begin to doubt whether Mr. Trump is sincere in his expressed desire to meet Mr. Xi, said Yun Sun, the director of the China program at the Stimson Center in Washington.

“They see him changing his position rapidly on a number of issues,” Ms. Sun said. “That translates into an almost fatalism for the Chinese, that they should aim to prepare for the worst case scenario, that’s their conclusion.”

Mr. Daines said he also expressed concern about China’s barriers to imports, beyond just tariffs, during his visit to Beijing. He declined to provide any specifics. But Montana politicians have long argued that China’s intermittent halts on imports of beef from the state are unfair trade barriers, and not the result of any actual concerns about mad cow disease, as Beijing contends.

Mr. Daines lived for six years in southern China in the 1990s as a project manager for Procter & Gamble, the American consumer products giant.

This weekend’s trip is Mr. Daines’s sixth to China since his election to the Senate in 2014, making him one of the few members of Congress who have continued traveling to the country even as relations have deteriorated.

A shorter open enrollment period, less help choosing a plan, higher health insurance premiums for many people — those are just a few changes now brewing that could affect your health insurance for 2026 if you have coverage through the Affordable Care Act marketplace. One shift is the scheduled end of more generous financial subsidies that, in recent years, have allowed many more people to qualify for marketplace plans with lower or no monthly premiums.

What’s more, the Trump administration, through the Centers for Medicare and Medicaid Services, proposed a new rule on March 10 involving about a dozen changes affecting enrollment and eligibility in the marketplaces. The agency, which oversees the marketplaces, said the rule was intended to improve affordability while “maintaining fiscal responsibility.”

Some health insurance experts, however, say the changes could make it more challenging for people to enroll in or renew coverage. If it becomes final, the rule will “restrict marketplace eligibility, enrollment and affordability,” according to an analysis in the journal Health Affairs that was co-written by Katie Keith, director of the Health Policy and the Law initiative at Georgetown University Law Center.

The public still has a few weeks to comment on the proposal. The administration is likely to move quickly to write a final version because insurers are now developing rates for health plans for 2026, Ms. Keith said.

Here are some of the possible changes to look out for.

Why is extra financial help for premiums set to end?

Enhanced premium help, first offered in 2021 as part of the federal government’s pandemic relief program, was extended through 2025 by the Inflation Reduction Act. The more generous subsidies increased aid to low-income people who already qualified for financial help under the Affordable Care Act, and added aid for those with higher incomes (more than $60,240 for individual coverage in 2025 coverage) who didn’t previously qualify.

The extra subsidies, given in the form of tax credits, helped marketplace enrollment balloon to some 24 million people this year, from about 12 million in 2021. The average enhanced subsidy, which varies by a person’s income, is about $700 per year, said Cynthia Cox, a health care expert at KFF, a nonprofit research group.

Unless Congress renews them, however, the extra subsidies will expire at the end of this year. Almost all marketplace enrollees would see “steep” premium increases in 2026, according to a KFF analysis. And about 2.2 million people could become uninsured next year because of higher premiums, the Congressional Budget Office estimates.

While the extra help has expanded coverage, it comes at a price. If made permanent, the more generous subsidies would cost $335 billion over the next 10 years, according to budget office projections.

With Republicans in control of Congress, it’s unclear if Democrats can broker a deal to continue the Biden-era enhanced subsidies.

How would open enrollment change for Obamacare plans?

The Trump administration’s proposed rule would shorten, by roughly four weeks, the annual window when people select coverage for the coming year. Open enrollment would start on Nov. 1 and end on Dec. 15 for all marketplace exchanges. Currently, the federal end date is Jan. 15, and some state exchanges keep enrollment open as late as Jan. 31.

In a fact sheet about the rule, the administration said the reasons for the change included reducing “consumer confusion” and aligning the window more closely with enrollment dates for many job-based health plans.

However, consumer advocates say that if the goal is to encourage enrollment, a January deadline makes sense. People are often busy during the year-end holiday season, so the extra weeks give people more time to consider their coverage, said Cheryl Fish-Parcham, director of private coverage at Families USA, a health insurance advocacy group.

Louise Norris, a health policy analyst at Healthinsurance.org, a consumer information and referral website, said a mid-December deadline could put some people in a bind.

Most people covered by marketplace plans are automatically re-enrolled for the coming year, but some may not realize that their premium has changed until they get a bill in January. Under the current January open enrollment deadline, if they can no longer afford their plan, they can still switch to less expensive coverage starting in February. “You have a ‘do over,’” Ms. Norris said. But if the enrollment deadline moves to December, they could be faced with a more costly plan, or dropping coverage.

Would special enrollment windows be affected?

Most people can’t sign up for Obamacare coverage outside open enrollment unless they have a big life event, like losing a job, getting married or having a baby, that qualifies them for a special enrollment window. But in 2022, an exception was created to allow low-income people (annual income of up to $22,590 for individual coverage in 2025) to enroll year-round.

The Trump administration’s proposed rule would abolish this option, which has been available in most states. The agency says it is ending the special enrollment period for low-income people because of concern that it contributes to “unauthorized” enrollments, including when rogue brokers enroll people in plans without their knowledge. The exception may end sometime this year, before open enrollment begins, health experts said.

People who have delayed seeking coverage should consider checking their eligibility now, Ms. Norris said. “That opportunity might go away well before open enrollment,” she said.

In recent years, Ms. Norris said, Healthcare.gov has verified eligibility for special enrollment periods only if the stated reason was a loss of other coverage, the most common reason. But the new rule, citing an apparent increase in “misuse and abuse” of special enrollment periods, would reinstate verification for all reasons.

“We know the more hoops people have to jump through, the less likely they are to enroll,” Ms. Norris said.

Will ‘dreamers’ still be eligible for coverage?

No. The administration’s proposed rule would exclude DACA recipients, known as “dreamers,” from Affordable Care Act health plans. (DACA stands for Deferred Action for Childhood Arrivals, a program adopted in 2012 that applies to certain undocumented immigrants brought to the country as children.) DACA recipients are protected from deportation and can work legally. They were given access to marketplace insurance plans in late 2024 under the Biden administration and remain eligible in all but 19 states, where an injunction prohibits their enrollment, according to the National Immigration Law Center. (The legal status of the dreamers generally remains uncertain because of an ongoing court challenge.)

Where can I share my opinion about the proposed rule?

Public comments can be submitted online or by mail until April 11. Details are available on the Federal Register website.

Will I be able to get help choosing a marketplace plan?

The Centers for Medicare and Medicaid Services in February cut funding for “navigators,” helpers who guide people through selecting a health plan, to $10 million this year, from almost $100 million under the Biden administration. Navigator groups also conduct outreach and education, and help people who aren’t eligible for marketplace plans enroll in Medicaid, according to KFF. The Trump administration argues that the navigator program isn’t cost effective.

Buried in China’s latest government budget were some numbers that add up to an alarming trend. Tax revenue is dropping.

The decline means that China’s national government has less money to address the country’s serious economic challenges, including a housing market crash and the near bankruptcy of hundreds of local governments.

Weak tax revenue also puts China’s leaders in a box as they square off with President Trump, who has imposed 20 percent tariffs on goods from China and threatened more to come. Beijing has less spare cash to help the export industries that are driving economic growth but could be hurt by tariffs.

The drop in tax collections leaves China’s leaders in an unfamiliar position. Until the last several years, China enjoyed robust revenue, which it used to invest in infrastructure, a rapid military buildup and extensive industrial subsidies. Even as economic growth has slowed gradually over the past 12 years, taking a dent out of consumer spending, tax revenue held fairly steady until recently.

Tax revenue fell further last year than ever before. And the only two previous declines in recent decades were under special circumstances: In 2020, China imposed an essentially nationwide pandemic lockdown for a couple of months, and in 2022, Shanghai endured a two-month lockdown.

China’s declining tax revenue now has several causes. A big one is deflation — a broad decline in prices. Companies and now the Chinese government find themselves with less money to make monthly payments on their debts.

Since September, Chinese officials have promised several times that they were on the cusp of doing what practically every foreign and Chinese economist recommends: spending more money to help the country’s beleaguered consumers with such measures as higher pensions, better medical benefits, more unemployment insurance or restaurant vouchers. But again and again, including on Sunday, they have laid out ambitious programs without providing more than a smidgen of extra spending.

The usual explanation for the frugality lies in longstanding opposition from Xi Jinping, China’s top leader, who warned in a speech in 2021 that China “must not aim too high or go overboard with social security, and steer clear of the idleness-breeding trap of welfarism.”

But China’s 2025 budget, which the Ministry of Finance released on March 5, suggests a different explanation: The national government may not have the money. Despite record borrowing, it would be hard-pressed to find the money needed to stimulate consumption.

Overall tax revenue fell 3.4 percent last year. That might not look like a lot. But it is a sizable divergence from the overall economy, which according to official statistics grew 5 percent before being adjusted for deflation.

Falling tax revenue means that China’s budget deficits are widening not because of extra government spending to help the economy, but because there is less money coming into the till. The problem has been worsening for years at local governments, which have plummeting revenues from selling state land, and has spread to the national government.

Fitch Ratings calculates that overall revenue for the national and local governments — including taxes and land sales — totaled 29 percent of the economy’s output as recently as 2018. But this year’s budget indicates that overall revenue will be just 21.1 percent of the economy in 2025.

Roughly half of the decline comes from plummeting revenue from land sales, a well-documented problem related to the housing-market crash, but the rest comes from weakness in tax revenue, a new problem.

That adds up to a huge sum of money. If overall revenue had kept up with the economy over the past seven years, the Chinese government would have another $1.5 trillion to spend in 2025.

China announced this month that it would allow its official target for the budget deficit to increase to 4 percent this year, after trying to keep it near 3 percent ever since the global financial crisis in 2009. But analysts say the true deficit is already much larger, because China is quietly counting a lot of long-term borrowing as though it were tax revenue.

Comparing spending only with actual revenue, without the borrowing, the Finance Ministry’s budget shows a deficit equal to almost 9 percent of the economy. In 2018, it was only 3.2 percent.

“Deficits are quite high and debt is rising quite quickly, so they are fiscally challenged,” said Jeremy Zook, a director of Asia and Pacific sovereign ratings at Fitch.

The biggest taxes in China are value-added taxes, a kind of sales tax that the government collects on practically every transaction, from rent to refrigerators. Last year, revenue from value-added taxes fell short of expectations by 7.9 percent.

The word “deflation” is prohibited in official Chinese documents, so the ministry came up with a euphemistic explanation: “This decrease was mainly due to the fact that the producer prices were lower than expected.”

Producer prices, essentially wholesale prices calculated as goods leave factories and farms, fell 2.3 percent in China last year.

Revenue from value-added taxes began weakening in 2018. That was when the government cut these taxes sharply for exporters to help them offset the impact of tariffs imposed by President Trump in his first term.

The cost of that tax break has soared since then as China’s exports have surged, producing a trade surplus of almost $1 trillion last year even as the rest of the economy stagnated.

Another problem lies in falling salaries and rising layoffs, especially during the second half of last year. Income taxes collected from individuals were 7.5 percent below expectations last year, the Finance Ministry said in its budget.

China’s own steep tariffs on imports are another large source of revenue. But having lost much of their savings in the housing market crash, China’s consumers have cut back on purchases of imports like handbags and perfume, while prices have fallen for many imported goods. So revenue from customs duties was 9.2 percent below forecasts last year, the Finance Ministry said.

This year’s financial picture could be even worse than the budget anticipates. The Finance Ministry’s budget repeated many of the same optimistic assumptions about tax revenue and overall economic performance that it made last year.

Governments in the West derive considerable revenue from taxes on investment gains, inheritances and real estate. But China has no taxes on investment gains or inheritances and almost none on real estate.

The general lack of real estate taxes lies at the root of a separate problem: China’s local governments are also running out of money. Until recently, they derived up to 80 percent of their revenues from selling land to property developers.

But those sales have plummeted since the housing crash began in 2021, which has gutted demand for new apartments and bankrupted many developers.

Local governments are responsible for most pensions, medical benefits and other social spending in China. The national government has been selling extra bonds to raise money for bailing out the weakest local governments, many of which are behind on their debts. The national government has called for local governments to step up social spending but, short on cash itself, has offered scant new financial assistance.

And new taxes are not likely forthcoming, according to Jia Kang, a retired research director at the Finance Ministry and still one of China’s most influential voices on tax policy. He said in an interview that public opposition to inheritance taxes is strong, while taxes on investment gains or real estate would hurt stocks or the housing market.

One factor not causing China’s tax challenges is fraud or tax evasion, Mr. Jia said. The procedures for checking on payments have become very detailed, he said. “It is difficult to cheat in this system.”

Siyi Zhao contributed research.