WASHINGTON — Democrat Adam Schiff stood on the Senate floor almost five years ago as a House impeachment manager and made a passionate case that Donald Trump should be removed from office for abusing the power of the presidency. “If right doesn’t matter, we’re lost,” he told the senators, his voice cracking at one point.

The Republican-led Senate wasn’t convinced, and senators voted to acquit Trump on the Democratic-led impeachment charges over his dealings with Ukrainian President Volodymyr Zelenskyy. Trump would survive a second impeachment a year later after his supporters stormed the Capitol and tried to overturn his defeat.

Now Trump is headed back to the White House, politically stronger than ever and with a firm hold over what will be a unified Republican Congress. And Schiff, one of Trump’s biggest foils, was sworn into the Senate on Monday as part of a Democratic caucus that is headed into the minority and has been so far restrained in opposing the returning president, taking more of a wait-and-see approach in the weeks before he is sworn into office.

As California’s newest senator, Schiff says he’s not going to shy away from familiar territory — opposing Trump when he feels it necessary. But he’s also hoping to be known for bipartisanship, as well, after campaigning in Republican areas of his state and working to learn more about rural issues that weren’t in his portfolio in his urban Los Angeles House district.

“I think being there and letting folks get to know me, kick the tires a bit, helps overcome some of the sort of Fox News stereotypes,” Schiff said of the conservative news channel’s focus on him as he challenged Trump in his first term. He says he also sees that outreach as a way to gain insight into Democrats’ way forward after losses in the November elections.

Schiff was sworn in weeks before the new Congress convenes on Jan. 3 because he is filling the seat of longtime Democratic Sen. Dianne Feinstein, who died last year. He is entering the Senate alongside Democratic House colleague Andy Kim of New Jersey, who is filling the term of former New Jersey Sen. Bob Menendez after he was convicted on federal bribery charges and resigned.

Bipartisanship was important to Feinstein, who often worked across the aisle and developed close relationships with other senators. But her work with Republicans also drew frequent criticism from California’s liberal voters.

Feinstein “was able to do a couple things simultaneously, which I’m going to need to try to do as well, and that is work with others to deliver for the state, work across party lines to get things done, and at the same time, stand up and defend people’s rights and their freedom and their values when those things are threatened,” Schiff told The Associated Press in an interview ahead of his swearing-in.

He says those priorities will frequently be at odds in the era of Trump, “and so I’ll have to try to do both.”

Democratic Sen. Brian Schatz of Hawaii, who has spent time with Schiff as he prepares to enter the Senate, says he thinks Schiff has the “right approach” in asking questions of other senators and refraining from “opining at every opportunity.”

“Everybody understands his capabilities, but he also understands that he’s a freshman,” Schatz says, and it’s appreciated when “someone of his stature understands that he’s joining a team here.”

Still, Schiff, who was censured by House Republicans last year for his involvement in investigations into Trump’s ties to Russia, won’t be able immediately to shake his longtime role as a chief Trump antagonist. The former House Intelligence Committee chairman is more well-known than most of his fellow incoming freshmen, and he has been calling Trump out on social media in recent weeks and criticizing some of his Cabinet nominees as many of his fellow Democrats have chosen to remain quiet.

Schiff posted on X last week that FBI director nominee Kash Patel, a former GOP staffer on the House intelligence panel, is “more suited as internet troll than FBI Director” and the “Senate must reject him.”

He could become part of the story as well as Trump has vowed revenge on people he views as his political enemies. President Joe Biden has been considering preemptive pardons for aides and allies like Schiff who tried to hold Trump accountable for his efforts to overturn the 2020 election. Trump once suggested Schiff should be arrested for treason and has called him an “enemy from within.”

Schiff, though, says he doesn’t think that’s necessary. He said Biden shouldn’t use his remaining days in office to defend him or any others who are in Trump’s crosshairs.

And the former prosecutor has long experience in defending himself from Republican attacks. After the House censure, which happened when fellow California Rep. Kevin McCarthy was speaker and Schiff was already running for Feinstein’s Senate seat, Schiff traveled to McCarthy’s district and met with local leaders. When a conservative news outlet there asked him what he thought of McCarthy calling him a liar, “I responded something along the lines of, well, coming from Kevin, I’m sure he means that as some form of a compliment,” Schiff said.

Schiff is unlikely similarly to go after his colleagues in the Senate, which he says “is a very different place culturally than the House.” He’s already tried to make inroads with Republicans, including incoming Sen. Tim Sheehy of Montana, whom he has talked to about working together on wildfire legislation important to both of their states.

And he could possibly win some grudging respect from more veteran Senate Republicans, some of whom praised him during the 2020 impeachment trial even as they vehemently disagreed with his premise and voted not to convict Trump.

After the first day of arguments, South Carolina Sen. Lindsey Graham shook his hand and told him he was doing a good job. South Dakota Sen. John Thune, who will become Senate majority leader next year, said at the time that Schiff “was passionate and his case has been well articulated.”

Schiff said he got the sense that some Republican senators “were a bit surprised that I wasn’t this caricature,” and also that the Senate is a more collegial place than the House.

“I don’t think it was a hurtful introduction,” he said.