WASHINGTON — The Senate Foreign Relations Committee split along party lines Monday to endorse Rex Tillerson as the country’s next secretary of state, setting up a confirmation vote in the full Senate that is all but guaranteed to succeed.

Republicans unanimously backed Tillerson in the 11-10 vote, after key Republicans who had voiced criticism of Tillerson opted to support his nomination.

Chief among them was Sen. Marco Rubio, R-Florida, a committee member who announced Monday morning that he would support Tillerson despite concerns about how Tillerson would approach Russia and other countries Rubio counts as human rights violators, resolving the final major question surrounding Tillerson’s bid to be confirmed as the nation’s top diplomat.

“My concern was that Mr. Tillerson would be an advocate for, and would pursue a foreign policy of, dealmaking, at the expense of traditional alliances and at the expense of the defense of human rights and democracy,” Rubio explained to the committee Monday.

Several Democrats on the Foreign Relations Committee expressed similar concerns, and elected not to support Tillerson’s nomination on those grounds. Democrats also complained that Tillerson had not answered many of their questions directly, and expressed alarm that the former ExxonMobil chief had advocated a military response to several conflicts, from the annexation of Crimea to the ongoing dispute with Beijing in the South China Sea.

“In my view the secretary of state should be leading with more diplomacy, and I found it disturbing that that seemed to be not his first reaction,” said committee ranking member Ben Cardin, D-Maryland.

But Tillerson’s confirmation was effectively sealed Sunday, when Republican Sens. John McCain of Arizona and Lindsey Graham of South Carolina, both of whom had criticized him strongly, announced they would support his bid in the full Senate.

Rubio announced his decision just hours before the Foreign Relations Committee voted on Tillerson.

Rubio’s backing came after weeks of deliberation and an intense behind-the-scenes effort by Tillerson allies to win him over.

Tillerson was the first big test of how Rubio plans to deal with Trump, with whom he clashed in the presidential campaign. By voting yes, he will spare himself what his allies anticipated would have been an angry backlash from the new administration in private.

“In making my decision on his nomination, I must balance these concerns with his extensive experience and success in international commerce, and my belief that the president is entitled to significant deference when it comes to his choices for the Cabinet,” Rubio said in his statement.

But he added a note of warning at the end: “Upcoming appointments to critical posts in the Department of State are not entitled to and will not receive from me the same level of deference I have given this nomination.”

Rubio said that while he found some of Tillerson’s responses to his questions encouraging, he remained troubled by others, including his unwillingness to say Russian President Vladimir Putin had committed war crimes.

Democrats complained that Tillerson had not submitted his tax returns to the committee, urging a change in policy to require such paperwork going forward — and expressed frustration that Tillerson had not given specific answers to many of the more than 1,000 questions to which he responded.

“I’ve looked at those responses, and they’re not responses to the questions that are asked,” Cardin said.

Senate Foreign Relations Chair Bob Corker, R-Tennessee, defended Tillerson’s efforts, accusing Democrats of “asking silly, silly, ridiculous, elementary questions that have nothing to do with somebody serving as secretary of state.” He added that he hopes the committee does not adopt a policy of asking for nominees’ tax returns in the future “because most of those are used for gotcha questions.”

Monday’s committee vote on Tillerson came amid a push by Republicans to swiftly confirm Trump’s nominees. Senate Majority Leader Mitch McConnell, R-Kentucky, said in an interview on “Fox News Sunday” that he believes “we’ll be able to confirm the president’s entire Cabinet.”

But Democrats have resisted, or at least sought to slow the progress of some nominees. The Senate planned to spend up to six hours Monday debating the nomination of Rep. Mike Pompeo, R-Kansas, to head the CIA before voting on him. Some Democrats pushed for the time to discuss the nomination while Republican leaders wanted to vote on him last Friday.

Rubio was getting an onslaught of calls, texts and notes urging him to back Tillerson, those close to him said.

Rubio donors and other supporters who served as Tillerson boosters reached out early and often to try to nudge the senator to back Trump’s nominee, including many from Texas, Tillerson’s home state. He heard from former Vice President Dick Cheney late last year.

Last week, Rubio held a meeting with Tillerson, now-Vice President Mike Pence and now-White House Chief of Staff Reince Priebus, according to two people familiar with the meeting.