Marco Rubio, the Republican senator from Florida named by Donald J. Trump to be the next secretary of state, was warmly welcomed by senators from both parties at his confirmation hearing on Wednesday. He has served for years on the Foreign Relations and Intelligence Committees in the Senate, and is known as a lawmaker devoted to the details of foreign policy.

“I believe you have the skills and are well qualified to serve as secretary of state,” Senator Jeanne Shaheen, Democrat of Hampshire, said in her opening remarks.

The notable lack of tension at the hearing indicated that Mr. Rubio would almost certainly be confirmed quickly.

Republican and Democratic senators agree on the biggest U.S. challenges.

From the lines of questioning, it was clear what senators want Mr. Rubio and the Trump administration to focus on: China, Russia, North Korea and Iran. Mr. Rubio himself pointed to those four powers — what some call an “axis” — in his opening remarks.

They “sow chaos and instability and align with and fund radical terror groups, then hide behind their veto power at the United Nations and the threat of nuclear war,” he said. As permanent members of the U.N. Security Council, China and Russia have veto power over U.N. resolutions.

Mr. Rubio repeatedly singled out the Chinese Communist Party for criticism, and, unlike Mr. Trump, he had no praise for any of the autocrats running those nations.

He did say the administration’s official policy on Ukraine would be to try to end the war that President Vladimir V. Putin of Russia started, and that leaders in both Kyiv and Moscow would need to make concessions. U.S. officials say Russia has drawn its allies and partners into the war, relying on North Korea for troops and arms, Iran for weapons and training, and China for a rebuilding of the Russian defense industrial base.

Rubio’s stance on Israel and Gaza is firmly within a foreign policy consensus in Washington.

Mr. Rubio defended Israel’s conduct in the war in Gaza, blaming Hamas for using civilians as human shields and calling the deaths of tens of thousands of Palestinians in Gaza, most of them non-combatants, “one of the terrible things about war.”

He expressed concern about threats to Israel’s security. “You cannot coexist with armed elements at your border who seek your destruction and evisceration, as a state. You just can’t,” he said.

When asked whether he believed Israel’s annexing Palestinian territory would be contrary to peace and security in the Middle East, Mr. Rubio did not give a direct answer, calling it “a very complex issue.”

Mr. Rubio’s hearing was about two hours in when the committee’s chairman announced that Israel and Hamas had sealed an agreement to begin a temporary cease-fire and partial hostage release in Gaza. An initial hostage and cease-fire agreement, reached in November 2023, fell apart after a week.

Rubio supports U.S. alliances, despite Trump’s persistent attacks on them.

Mr. Rubio called the North Atlantic Treaty Organization, which Mr. Trump has repeatedly criticized, “a very important alliance” and insisted that Mr. Trump was a NATO supporter. But he also backed Mr. Trump’s argument that a strong NATO requires Europe to spend more money on its collective defense.

The United States, he said, must choose whether it will serve “a primary defense role or a backstop” to a self-reliant Europe.

Though many Senate colleagues praised him, Rubio has detractors.

Some prominent Trump supporters remain distrustful of Mr. Rubio. They recall his vote to certify the 2020 election results despite Mr. Trump’s false claims of election fraud. And they consider Mr. Rubio’s foreign policy record dangerously interventionist.

Mr. Rubio has long been a hawkish voice on national security issues, often in ways that clash with Mr. Trump’s views, even if the ideas are conventional ones among centrist Republican and Democratic politicians.

In the past, Senator Rand Paul, Republican of Kentucky, has criticized Mr. Rubio for advocating aggressive American intervention overseas. Mr. Paul has been outspoken in pushing for less use of U.S. troops abroad and is skeptical about whether economic sanctions can lead to positive outcomes.

On Wednesday, Mr. Paul pointedly asked Mr. Rubio whether he saw any way to work with China rather then persisting in attacks on Beijing, and he also questioned the wisdom of many American and European policymakers who insisted that Ukraine must be admitted to NATO.