Rubio, the Republican senator from Florida, is among the least controversial of Trump’s nominees and vote was decisive, 99-0. Another pick, John Ratcliffe for CIA director, is also expected to have a swift vote, as soon as Tuesday. Action on others, including former combat veteran and Fox News host Pete Hegseth for defense secretary, is possible later in the week.

“Marco Rubio is a very intelligent man with a remarkable understanding of American foreign policy,” Sen. Chuck Grassley of Iowa, the senior-most Republican, said as the chamber opened.

It’s often tradition for the Senate to convene immediately after the ceremonial pomp of the inauguration to begin putting the new president’s team in place, particularly the national security officials. During Trump’s first term, the Senate swiftly confirmed his defense and homeland security secretaries on day one, and President Joe Biden’s choice for director of national intelligence was confirmed on his own Inauguration Day.

With Trump’s return to the White House, and his Republican Party controlling majorities in Congress, his outsider Cabinet choices are more clearly falling into place, despite initial skepticism and opposition from both sides of the aisle.

Rubio, who was surrounded by colleagues in the Senate chamber, said afterward he feels “good, but there’s a lot of work ahead.”

“It’s an important job in an important time, and I’m honored by it,” Rubio said.

Senate Majority Leader John Thune moved quickly Monday, announcing he expected voting to begin “imminently” on Trump’s nominees.

Democrats have calculated it’s better for them to be seen as more willing to work with Trump, rather than simply mounting a blockade to his nominees. They’re holding their opposition for some of his other picks who have less support, including Tulsi Gabbard for director of national intelligence and vaccine skeptic Robert F. Kennedy Jr. for health secretary.

Senate Democratic Leader Chuck Schumer said his party will “neither rubber-stamp nominees we feel are grossly unqualified, nor oppose nominees that deserve serious consideration.”

Rubio, he said, is an example of “a qualified nominee we think should be confirmed quickly.”

Senate committees have been holding lengthy confirmation hearings on more than a dozen of the Cabinet nominees, with more to come this week. And several panels are expected to meet late Monday to begin voting to advance the nominees to the full Senate for confirmation.

The Senate Foreign Relations Committee unanimously advanced Rubio’s nomination late Monday. The Senate Armed Services Committee and Senate Intelligence Committee, respectively, voted to move the nominations of Hegseth and Ratcliffe. And the Homeland Security and Government Affairs Committee advanced nominees Kristi Noem as homeland security secretary and Russell Vought as director of the Office of Management and Budget, but with opposition.

Rubio, a well-liked senator and former Trump rival during the 2016 presidential race, has drawn closer to the president in recent years. He appeared last week to answer questions before the Foreign Relations Committee, where he has spent more than a decade as a member.

As secretary of state, Rubio would be the nation’s top diplomat, and the first Latino to hold the position. Born in Miami to Cuban immigrants, he has long been involved in foreign affairs, particularly in South America, and has emerged as a hawk on China’s rise.

During his confirmation hearing last week, Rubio warned of the consequences of America’s “unbalanced relationship” with China. While he echoes Trump’s anti-globalist rhetoric, Rubio is also seen as an internationalist who understands the power of U.S. involvement on the global stage.

Rubio cultivated bipartisan support from across the aisle, both Republicans and Democrats. He takes over for outgoing Secretary of State Antony Blinken, who has said he hopes the Trump administration continues Biden’s policies in the Middle East to end the war in Gaza and to help Ukraine counter Russian nomination.

The Senate is split 53-47, but the resignation of Vice President JD Vance and, soon, Rubio drops the GOP majority further until their successors arrive. Republicans need almost all every party member in line to overcome Democratic opposition to nominees.

Objection from any one senator, as is expected with Hegseth and several other choices, would force the Senate into procedural steps that would drag voting later into the week.