PHOENIX — Arizona was already expected to be one of the most closely contested states in November’s U.S. presidential election. But a ruling this week instituting a near-total abortion ban supercharged the state’s role, transforming it into perhaps the nation’s most critical battleground.

This Sunbelt state with a fierce independent streak has long been at the forefront of the nation’s immigration debate due to its 378-mile border with Mexico and its large Hispanic and immigrant populations. It now moves to the center of the national debate over reproductive rights after the U.S. Supreme Court ended a federally guaranteed right to abortion.

Abortion and immigration have been two of this year’s biggest political issues. No battleground state has been affected more directly by both than Arizona.

“Do not underestimate this,” Democratic pollster John Anzalone, who polls for President Joe Biden’s reelection campaign, said of the Arizona abortion ruling. “It’s dynamic-changing.”

Biden and presumptive Republican nominee Donald Trump are expected to fight hard to win Arizona after Biden carried the state four years ago by less than 11,000 votes.

In addition to the presidency, the U.S. Senate majority may be decided by the state’s high-profile contest between Republican Kari Lake and Democratic Rep. Ruben Gallego in the race to replace retiring Sen. Kyrsten Sinema, an independent who caucuses with Democrats.

The state Supreme Court’s ruling reviving an abortion ban passed in 1864 also added rocket fuel to Democrats’ push to add a question to the November ballot asking voters to approve a constitutional amendment protecting the right to abortion until viability, when a fetus could survive outside the womb. Later abortions would be allowed to save the woman’s life or protect her physical or mental health.

Trump campaign senior adviser Chris LaCivita, who also serves as chief of staff to the Republican National Committee, described Arizona as “a key part of the strategy.”

He declined to discuss any specifics on strategy but disagreed that the abortion ruling fundamentally changed Arizona’s dynamics.

“Is abortion an issue that the campaign has to deal with in the battleground states — and more specifically in Arizona? Absolutely. We feel that we are doing that and we are exceeding what we need to do,” LaCivita said, even as he suggested other issues would be more salient for most Arizona voters this fall.

“The election is going to be determined really in large part based on the key issues that the vast majority of Arizonans have to deal with every single day, and that’s, ‘Can I afford to put food on the table and feed my family and get in the car to go to work?’” he said.

Democrats are quick to note that they have won virtually every major election in which abortion was on the ballot since the June 2022 reversal of Roe v. Wade.

The Biden campaign on Thursday launched a statewide abortion-related advertising campaign that it said would reach seven figures, although ad tracking firms had yet to confirm the new investment. The new ads come in addition to a $30 million nationwide advertising blitz that was already underway, according to Biden campaign spokesman Kevin Munoz.

In the new ad, Biden links Arizona’s abortion restrictions directly to Trump.

“Your body and your decisions belong to you, not the government, not Donald Trump,” Biden says. “I will fight like hell to get your freedom back.”

Beyond the ad campaign, Vice President Kamala Harris is scheduled to appear in Arizona on Friday to highlight the Democrats’ dedication to preserving abortion rights.

Even without this week’s abortion ruling, Democrats were already betting big on Arizona this fall.

Biden’s team is on track to spend more than $22 million on Arizona advertising between April 1 and Election Day, according to data collected by the ad tracking firm AdImpact. That’s millions more than other swing states like Wisconsin, Georgia and Nevada. Only Pennsylvania and Michigan are seeing more Democratic advertising dollars.

Trump’s team, meanwhile, isn’t spending anything on Arizona advertising this month and hasn’t yet reserved any general election advertising in the state, according to AdImpact.

Yet Trump remains bullish on the state, which had backed a Republican presidential candidate in every election since 1996 before it narrowly supported Biden in 2020. They point to a modest shift among Hispanic voters, a core group in the Democratic coalition, which may be more open to Trump.

Meanwhile, Arizona Republicans are still bogged down by GOP infighting in a state where the party apparatus built and nurtured by the late Sen. John McCain has been usurped by Trump’s “Make America Great Again” loyalists.

The division came to a head in the 2022 primary for governor, when Trump and his allies lined up enthusiastically behind Kari Lake, while traditional conservatives and the business establishment backed her rival.

Lake won the primary. Rather than mend fences with the vanquished establishment, she gloated that she “drove a stake through the heart of the McCain machine.” She’s since made a more concerted effort behind the scenes to win over her GOP critics, with mixed results.

Lake, a major MAGA figure sometimes discussed as a potential Trump running mate, is now running in the state’s high-profile Senate race.

Like Trump, she has come out against the latest abortion ruling, arguing it is too restrictive. But two years ago, Lake called the abortion ban “a great law,” said she was “incredibly thrilled” that it was on the books and predicted it would be “setting the course for other states to follow.”

The ruling played straight into the hands of Gallego, her Democratic rival, who had already put abortion rights at the center of his pitch to Arizona voters.

“I think we were on our way to winning this,” he said in an interview. “I think what it does is it focuses people’s attention on abortion rights that maybe weren’t thinking about it as the most important thing or one of the top issues.”

Meanwhile, Anzalone, the Biden pollster, warned his party against overconfidence.

“It’s not going to be easy. These are all close races. I’m not getting ahead of myself in any way,” he said of the fight for Arizona this fall. “But we like the advantage we have there.”