This weekend, a small group of House Democrats calling for impeachment were joined by a Republican: Michigan Rep. Justin Amash.

Amash is the first Republican in Congress to call for impeachment, and his party defection was perhaps not surprising. As Vox’s Tara Golshan noted, Amash is libertarian and a member of the conservative House Freedom Caucus. He has called out President Donald Trump in the past. But his tweet thread was notable for the fact that it excoriated lawmakers in his own party who Amash said were turning a blind eye to the president’s conduct.

Here are my principal conclusions:

1. Attorney General Barr has deliberately misrepresented Mueller’s report.

2. President Trump has engaged in impeachable conduct.

3. Partisanship has eroded our system of checks and balances.

4. Few members of Congress have read the report. — Justin Amash (@justinamash) May 18, 2019

Amash’s statement likely won’t be a game changer for House Speaker Nancy Pelosi and her committee chairs — the most important people who get to decide how far to go on the subject. But it does add a bit more momentum to a nagging question Democrats have been dealing with (and putting off) for months: Do they try to impeach the president?

Pursuing articles of impeachment against Trump would be politically explosive. Democrats know the Republican-led Senate under Mitch McConnell won’t take the next step after impeachment — a trial in the Senate — and they doubt the public would support them. In March, just 36 percent of voters polled by CNN supported impeachment. That number has risen in subsequent months, with 45 percent of the public supporting impeachment, per a May Reuters/Ipsos poll. But it’s still an incredibly divisive topic, and one Pelosi would only entertain if she knew the vast majority of Americans, including Republicans, were on board.

Democrats know their best shot at getting rid of Trump is the 2020 presidential election. But at the same time, special counsel Robert Mueller laid out numerous instances of potential obstruction of justice by Trump in his report, and Democrats know they can’t just ignore it. The progressive wing of the Democratic Party has been vocally pushing for impeachment proceedings, but they need buy-in from committee chairs and House leadership.

“If we do nothing here, the president is going to be emboldened,” House Oversight Committee Chair Elijah Cummings said on CBS’s Face the Nation in April.

Pelosi has been extremely careful with her rhetoric on impeachment, saying Trump was “just not worth it” a few months ago. She’s largely held the line since then, repeating that committees can still investigate Trump without opening impeachment proceedings. But she also seems to think the president is trying to goad Democrats into impeaching him as a way to stoke controversy.

It’s not just about the Mueller report; now that the Trump administration is actively pushing back on all Democratic subpoenas, chairs of key House committees have suggested impeachment could be on the table should Trump’s behavior get too out of control. And although Pelosi has shown no indication she will actually launch proceedings, she has alluded to it in public talks.

“I think the president every day gives grounds for impeachment in terms of his obstruction of justice. You never say, blanketly, I’m not answering any subpoenas,” Pelosi said last week at a Georgetown University Law Center event. “Now I don’t want to impeach. I want them to give us the information before they have to spend too much money on lawyers.”

In other words, Pelosi is still on a fact-finding mission. Whether she finds enough facts to go down the road of impeachment is an open question.

The debate around impeaching Trump, briefly explained

House Democrats are split.

On one side, there’s a handful, including Reps. Rashida Tlaib (MI), Ilhan Omar (MN), Alexandria Ocasio-Cortez (NY), Al Green (TX), and Steve Cohen (TN), who have been vocal about their belief that Trump is unfit for office. Many of them have signed on to articles of impeachment. On the other side, a number of moderate Democrats believe impeachment is a distraction from issues like infrastructure and health care — the very things that got them to a Democratic majority in the first place. And then there are a bunch of people in the middle who aren’t ruling out impeachment but want more information before they make a decision.

The people with the most power to direct the party one way or the other — Pelosi and her committee chairs — fall somewhere in that middle category. For all of Pelosi’s reticence on impeachment, committee chairs including Nadler and House Intelligence Committee Chair Adam Schiff (D-CA) are talking about it more seriously since the redacted Mueller report came out.

“The obstruction of justice in this case is far worse than anything Richard Nixon did,” Schiff said during an ABC News interview last month. “The level of evidence in the Mueller report is serious and damning and in normal circumstances would be without question within the realm of impeachable offenses.”

Even Democrats skeptical of impeachment took notice of the 10 specific episodes in which Mueller investigated Trump for obstruction of justice. Part of Mueller’s reason for not charging Trump himself was clearly the Justice Department’s longstanding practice not to indict a sitting president. Instead, Mueller wrote that Congress gets to decide what happens next.

“I think there was a not-so-subtle invitation for Congress to now pick up oversight on the administration, dig into the facts, and decide what to do next,” Rep. Jason Crow (D-CO) told Vox.

Impeachment is a political exercise, and Democrats are afraid of that

The question of whether to impeach Trump is one where Democrats could be damned if they do and damned if they don’t. Because Congress is split between a Democratic House and a Republican Senate, Democrats are nervous that impeachment will be perceived as a political fight, especially if they rush into it.

As Vox’s Ezra Klein pointed out, “The founders could have made the impeachment process legal or automatic. Instead, they made it political and discretionary.”

Even though Trump’s 42 percent public approval rating is extremely low, Pelosi and the majority of her caucus only want to move toward impeachment if there’s something so bad that Republicans can also get on board. They remember when Republicans who impeached President Bill Clinton in the 1990s reaped the political consequences in the 1998 midterms, when they lost seats in the House and made few gains in the Senate. Historians later concluded that backlash against Republicans for Clinton’s impeachment resulted in the GOP’s weak showing in the midterms.

That history isn’t lost on Democrats, especially as they stare down a pivotal presidential election in 2020.

“We also have lessons from the Clinton impeachment that when you do impeachment for primarily political reasons, that also causes problems for the country,” Rep. Mary Gay Scanlon (D-PA), the vice chair of the House Judiciary Committee, told Vox. “This is not something the country can enter lightly, but by the same token, the country cannot have a president that undermines the rule of law.”

Crow, the Colorado moderate who unseated a five-term Republican incumbent last year, certainly isn’t an impeachment advocate. He wants to make sure Democrats don’t lose sight of what’s important to voters as they investigate Trump.

“I didn’t campaign on [impeachment]; I campaigned on the kitchen table issues,” he told Vox. “People in my community are concerned about immigration reform, gun violence, health care, but they also care about accountability.”

Censure: a potential alternative to impeachment

Pelosi wants Congress to continue with its current work, investigating the Trump administration for everything from potential obstruction of justice to family separation at the southern border to the administration’s attempts to sabotage the Affordable Care Act. She believes that work can continue without passing articles of impeachment but isn’t ruling out the option completely.

And for all the talk around impeachment, Congress has another option that would be far less divisive: censuring the president. At least two members expressed support for this idea on Monday’s conference call, although it’s unclear whether it has widespread support in the caucus.

A censure resolution is a formal statement of disapproval of the president, but it’s nonbinding and doesn’t lead to impeachment or expulsion. It is also exceedingly rare; Congress hasn’t censured the president since the US Senate censured Andrew Jackson in 1834. Jackson had clashed with the Senate after he tried to withdraw federal money from the Bank of the United States, after vetoing its charter.

The House just needs a simple majority to pass a censure resolution, so one could easily pass now. It would be tougher to pass in the Senate, where it would likely require 60 votes to get past the filibuster. However, Democrats could use a censure resolution as a test to see how many moderate Republicans are willing to censure Trump — and gauge how much support the president has in his own party after the Mueller report.

Scanlon pointed out that Congress could also pursue obstruction charges against Trump after he leaves office, noting it’s an option Mueller laid out “explicitly” in his report. Of course, one clear risk with that strategy is politicians often want to move on rather than rehash past events. In 1974, then-President Gerald Ford pardoned his predecessor Richard Nixon, and President Barack Obama didn’t try to hold members of the Bush administration accountable for launching the war in Iraq, despite public pressure.

The ball is still in Democrats’ court. No matter what they do next, Pelosi wants to make sure they are not rushing to judgment. She plans for this to be a deliberate process.

“We must show the American people we are proceeding free from passion or prejudice, strictly on the presentation of fact,” Pelosi wrote in her letter.