Washington • Nearly a quarter century since he first unsuccessfully sought a Senate seat from Massachusetts, Mitt Romney was sworn in as Utah’s newest senator on Thursday promising to fight for conservative causes while also being willing to criticize President Donald Trump when he believes it’s called for.

Romney, a former Massachusetts governor who lost to Sen. Ted Kennedy, D-Mass., in his first political bid in 1994, raised his right hand in the Senate chamber on Thursday to take the oath of office from Vice President Mike Pence only days after writing a damning opinion piece hitting Trump for his lack of presidential character.

“It’s an entirely new chapter and I really am very very much looking forward to it,” Romney said earlier Thursday morning.

Romney, the 2012 GOP presidential nominee, was sworn in with a small group that included Vermont Democratic Sen. Bernie Sanders, who lost his White House bid in 2016. Sen. Mike Lee and now-former Sen. Orrin Hatch, whose seat Romney is taking, escorted the freshman senator on the Senate floor.

Romney’s entrance to the Senate comes amid a partial government shutdown forced by some conservatives and Trump to require that any new funding bill include billions of dollars to build a physical wall along the U.S.-Mexican border. Democrats, who now control the House and hold enough Senate seats to block legislation, have been mostly steadfast in their opposition to Trump’s wall.

Romney, in a short interview before taking office, said he also wants a wall but wasn’t sure how he’d vote yet on legislation to re-open the government that didn’t include the border security money Trump is demanding.

“I'm not going to put a hard oar in the sand without seeing what the particulars of a piece of legislation might be,” Romney said.

“But I can tell you that I do favor a physical barrier on the southern border as well as the use of technology or whatever else is required to protect our border,” he continued. “That’s something that I’ve been in favor of for a long long time and I will support an effort to build a border wall. How that’s done, meaning how that’s done legislatively, and when it gets done legislatively, is something that I’m not an expert on yet and we’ll probably learn over the coming weeks.”

That said, Romney said he wasn’t happy with the current impasse where hundreds of thousands of federal workers are furloughed, others are working without pay and government services are curtailed.

“Shutdowns don't make a lot of sense in my opinion,” Romney said. “I know they're symbolic but it's a symbol that has a lot of pain associated with it for a certain number of people. And that's a pretty substantial number of people and it's not fair that those people suffer for something that's not their responsibility.”

Congress continues to receive pay during the shutdown.

Romney had been highly critical of Trump during the GOP primaries in 2016, calling him a “phony, a fraud,” but later, after Trump won, he sat down for dinner to discuss a potential job as secretary of state.

Since then, Romney has spoken out occasionally, mainly on Twitter, against Trump’s rhetoric.

His latest salvo came this week, when The Washington Post published an op-ed from Romney headlined, “The president shapes the public character of the nation. Trump’s character falls short.” Romney laid out, essentially, how he’s going to approach his new Senate gig and deal with this White House.

Thursday, Romney said he's not going to be a constant critic of the president but he wasn't going to be silent either.

“I expect that I'll continue to respond as I have in the past,” Romney said.

The new senator said he had not heard from the president or the White House since he was elected but has talked to people in the administration.

I'm not doing it again. I'm not running again,” Romney said. “There's just no way I run for president again. And we'll see whether anyone else does in our party ... and [whether] President Trump runs for re-election and whether he has a primary [challenge]. But time will tell. It's not going to be me.”

Romney, who has been a governor and chief executive but never a legislator, said he was learning the ropes and had 42 goals he’s jotted down so far. His basement office — temporary for a few months — was small and still being organized. The lamp on his desk still had tags on it and Romney showed off a flip-book of senators' pictures he’s been studying to recognize all his new colleagues.

There’s no question, though, that they all know him.

As Romney awaited the swearing in, he wandered the Senate floor talking with conservatives, moderates and liberals. He was excited to show Sen. Ted Cruz, R-Texas, the Bible he’d be sworn in on — one his dad, George Romney, used to become Michigan governor and Mitt Romney used to take the oath in Massachusetts.

Thursday afternoon, Pence performed a ceremonial swearing in for Romney, who then was slated to fly to Paris for the wedding of his eldest granddaughter this weekend.

There are no votes scheduled now to end the shutdown, but Romney joked to a crowd of supporters that he really hoped they don't call one while he's away.

“It would be really unfortunate to miss my first vote,” he said.

Romney's wife, Ann, praised her husband on his new position and offered a slight rebuke of Trump.

Romney, she said, is a “man of outstanding ethical character and that's something we need right now.”

He’ll serve on the committees on Foreign Relations; Health Education Labor and Pensions; Homeland Security; and Small Business.

A cheerful Hatch, who served 42 years in office, the longest of any Republican senator, walked into the Senate for the last time as a member Thursday morning.

“I never thought I’d be here 42 years,” he said