At a multi-candidate town hall on CNN, Sanders didn't say whether or not he supports impeachment on substantive grounds. Instead, he addressed the possible political ramifications of impeachment:

If for the next year, year-and-a-half, going right into the heart of the election, all that the Congress is talking about is impeaching Trump and Trump, Trump, Trump, and Mueller, Mueller, Mueller, and we're not talking about health care, we're not talking about raising the minimum wage to a living wage, we're not talking about combating climate change, we're not talking about sexism and racism and homophobia, and all of the issues that concern ordinary Americans, what I worry about is that works to Trump's advantage.

Warren has explicitly called for Trump's impeachment, writing in a series of tweets that "the House should initiate impeachment proceedings against the President of the United States." She accused Trump of obstructing justice, and said that a failure to impeach him for this "would inflict great and lasting damage on this country."

Harris also supports impeaching Trump, although with a bit of a caveat. At CNN's town hall, she said that "Congress should take the steps towards impeachment" due to what's in the Mueller report. However, she also noted that Trump can't be removed from office without a two-thirds majority vote in the Senate, and warned that Senate Republicans almost certainly won't provide those votes.

"I've not seen any evidence since I've been in the United States Senate that [Senate Republicans] will weigh on the facts instead of on partisan adherence to being protective of this president," Harris said. "So we have to be realistic about what might be the eventual result [of an impeachment vote]."

At a campaign stop in New Hampshire, Buttigieg said that Trump has "made it pretty clear he deserves impeachment," but that the decision of whether or not to impeach him is "for Congress to work out."

When asked at CNN's town hall if the House should impeach Trump, Klobuchar said that "the impeachment proceedings are up to the House," but didn't say whether or not she believes the president should be impeached.

In an interview with NPR, Hickenlooper said that Congress should wait for further developments before deciding whether to impeach Trump.

"We have to really push for an unredacted copy of the [Mueller] report that goes to Congress," Hickenlooper told NPR. "I think Mr. Mueller should testify in front of Congress, and then we can see in gory detail and in high-contrast color more clearly what went on and make a decision about impeachment."

According to the Associated Press, Booker told reporters in Nevada that "there’s a lot more investigation that should go on before Congress comes to any conclusions like [impeachment]."

When asked about impeachment by MSNBC's Andrea Mitchell, Gillibrand said that impeachment should be "on the table," but that she'd like to see an unredacted version of the Mueller report before any impeachment hearings proceed.

"Having read parts of the report, I believe there is a basis for obstruction of justice and to proceed to impeachment proceedings based on what we know," Gillibrand said. "But I would like to have the rest of the report fully known before we proceed and I would like to have the testimony taken."

In an an interview with CNN, Castro said that he thinks it would be "perfectly reasonable for Congress to open up [impeachment] proceedings" against Trump.

While running for the Senate in 2018, O'Rourke — who was then still a member of Congress — told CNN that he'd vote to impeach Trump. After becoming a private citizen and launching his presidential campaign, O'Rourke gave a slightly different response to the question of impeachment.

"I'm not asking Congress to do one thing or the other," he told reporters in March, according to the Dallas Morning News. "I'm just saying — you're asking me, has the president committed impeachable offenses? Yes. Period." He went on to say that "it's beyond a shadow of a doubt" that Trump has committed impeachable offenses.

When CNN's Jake Tapper asked him in late April if Trump should be impeached, Ryan said that he supports the House's investigations into Trump but confirmed that he doesn't think impeachment proceedings should be initiated just yet.

Swalwell told CNN in late April that "we're on that road [toward impeachment]," and that "we certainly got closer after the Mueller report" was released. However, he also said that Congress should obtain the full Mueller report and have Mueller testify before making a final decision on impeachment.

Messam thinks Trump should be impeached.

"Based on what is available I believe the President should be placed under impeachment proceedings and let the weight of the full report carry out the justice the American people deserve," Messam said in a statement to The Hill.

Inslee wrote on Twitter that "impeachment should not be off the table," and that Congress should continue its investigations into Trump and his administration.

While campaigning in New Hampshire, Moulton said that it's "not the right time to vote on impeachment because we don’t have all the facts yet," according to the Boston Herald.

Weld, who's challenging Trump for the 2020 Republican nomination, told ABC News that he "really doesn't think" impeachment should be on the table. Weld said that there's "more than enough evidence" for the House to impeach Trump, but that it would backfire politically because the GOP-controlled Senate won't vote to remove Trump from office.

"The upshot of 15 months of impeachment proceedings might be that the House looks like overzealous prosecutors and the president comes out smelling like a rose," Weld explained.

At a CNN town hall, Williamson said that she believes Trump has committed impeachable offenses, and accused him in he same breath of having "fascist leanings."

“Do I feel that he has committed impeachable offenses? Absolutely," Williamson said. "I think this president clearly has fascist leanings, and I think that all of us, conservatives as well as liberals, need to stop pretending that this isn’t true. So there are many things about the president behavior, his policies and so forth I would consider impeachable offenses.”

After the Mueller report was released, Gabbard told Fox News that she doesn't think Trump should be impeached.

"I don't think that we should defeat Donald Trump through impeachment," Gabbard said. "I think it's really important for us, in this country, to come together and have the American people vote to take Donald Trump out of office in 2020."

Delaney hasn't publicly addressed impeachment since the Mueller report was released, although in January 2018, he did vote to table an impeachment motion in the House.

Yang does not appear to have made any public comments regarding impeachment.

Gravel does not appear to have made any public comments regarding impeachment.

Although the 2020 candidates have many varying feelings about impeaching Trump, the decision ultimately lies with the 538 members of the federal Congress — only a handful of whom are also running for president in 2020.