WASHINGTON — Congress is back in town for the first time since late September, after a two-week recess stuffed with impeachment developments. That means we’ll soon get a much clearer view of where members stand on the biggest issue facing the country.

The basic political reality is that the Democratic-controlled House is almost certain to impeach President Trump, and the GOP-controlled Senate is highly unlikely to vote to remove him from office. That would take 67 senators, meaning that at least 20 of the 53 Republican senators would need to split from Trump for him to be removed.

But while few Republicans have publicly rebuked Trump’s actions at this point, most of them have been conspicuously silent or cautious during their time back in their states, a sign that many are not eager to defend the president’s actions — and worried what else might come out.

"Folks are being careful because they don’t know what’s going to be out there,” said one Republican strategist who’s talked to a number of Senate offices in recent days. “It’s a Pandora’s box. Things keep coming out. If I were a senator, even in a safe seat, I’d be really careful about what I say."

Polls show support for impeachment rising, and some have found that a narrow majority of Americans currently back removing Trump from office. But while that creates pressure on swing-state senators facing re-election this fall, most of them have calculated they have a lot more to fear from a fractured base or a primary challenge than they do from standing behind Trump (Sen. Thom Tillis, R-N.C., learned this the hard way.). Sens. Joni Ernst (R-Iowa), Cory Gardner (R-Colo.), and Martha McSally (R-Ariz.) are so far standing by their man, or bending over backwards to avoid criticizing him.

The group that Trump needs to worry about most isn’t the handful of swing-state Republicans facing re-election who have their fingers in the political wind. It’s the moderates and institutionalists, some of whom are retiring, and who worry more about the history books than what voters think right now.

Some of them have already shown a willingness to stand up to Trump.

A dozen Republican senators have already split with the White House on an issue many saw as unconstitutional: voting to overturn Trump’s emergency declaration used to raid military funding for his border-wall pet project.

“Those are the ones who are definitely independent of the president,” said former Sen. Mark Kirk (R-Ill.). “The old mod squad of my colleagues, like Susan [Collins] and Lisa [Murkowski], are the ones to look at who, no matter what, will try to do the right thing. And that may upset the president.”

A dozen Republicans broke with Trump last March: Sens. Lamar Alexander (R-Tenn.), Roy Blunt (R-Mo.), Collins (R-Maine), Mike Lee (R-Utah), Jerry Moran (R-Kan.), Murkowski (R-Alaska), Rand Paul (R-Ky.), Rob Portman (R-Ohio), Mitt Romney (R-Utah), Marco Rubio (R-Fla.), Pat Toomey (R-Pa.), and Roger Wicker (R-Miss). All except Rubio (who didn’t vote) voted the same way when the issue came before them again just a few weeks ago.

Members of that group have been among the most outspoken critics of Trump’s actions in pressuring Ukraine to investigate Vice President Joe Biden. Romney called Trump’s July 25 call with Ukraine’s president “troubling in the extreme,” and he called public comments asking China and Ukraine to investigate Biden “wrong and appalling.”

Collins is the only Republican facing a tough re-election who’s been willing to criticize Trump. She called Trump’s call for China’s help “completely inappropriate” and promised to take the impeachment process seriously. Murkowski made it clear she was taking the impeachment process seriously and was “trying to be as educated as I possibly can” about the facts before her. Blunt, a member of Senate GOP leadership, said “putting the facts together on the most recent House allegation is important,” even as he blasted House Democrats for a “partisan exercise.”

Some of those members have defended the president, however. Lee, Moran, Paul, and Wicker lambasted Democrats’ impeachment effort and have dismissed concerns about Trump’s actions. And others took the position that while Trump’s actions weren’t OK, they also weren’t impeachable. Alexander, who is retiring, called Trump’s actions “inappropriate,” though he said impeachment would be “a mistake.” Portman told reporters it's "not appropriate for a president to engage a foreign government with an investigation with a political opponent,” but he said it wasn’t an impeachable offense.

Some of the Senate’s other more establishment-minded Republicans should be closely watched as well.

Sen. Ben Sasse (R-Neb.) went from a Never Trump Republican to one who’s been strikingly quiet amid Trump’s regular scandals. He just got Trump’s endorsement for his 2020 re-election. But he decided that Trump’s call for help from China was a bridge too far.

“Americans don’t look to Chinese commies for the truth. If the Biden kid broke laws by selling his name to Beijing, that’s a matter for American courts, not communist tyrants running torture camps,” he told the Omaha World-Herald.

Retiring Sens. Mike Enzi (R-Wyo.) and Pat Roberts (R-Kan.) have been notably quiet about their thoughts. Enzi offered a measured, noncommittal statement and Roberts has stayed silent.

While House lawmakers are already staking out their positions. Senators have the luxury of time. They can simply say they’ll wait until all the facts come out, as they’re waiting on the House to do its investigation. But once they return on Tuesday to a crush of reporters and consult one another for the first time after a long stretch at home, we should get a better sense of whether a real number of them are ready to show some spine — or whether most will just fall in line once they can get on the same page in meetings next week.

"I just don’t know what kind of a world we’re walking into next Tuesday,” Ron Bonjean, a veteran GOP Senate strategist, told VICE News on Friday. “But we’re going to get a lot more reactions next week.”