DAVENPORT, Iowa — Bernie Sanders made some of his most pointed comments in support of impeaching Donald Trump on Tuesday, saying he believed the president had committed a number of impeachable offenses, but also expressed deep misgivings about supporting a move that could embolden Republican voters only to fall short of success in Congress.

“Enough is enough,” Sanders said before reiterating his previous call for an impeachment inquiry by the Judiciary Committee in the House of Representatives.

The Vermont senator, taking questions at a press conference here in Iowa on Tuesday, declined to commit on supporting impeachment if it came to a vote in the Senate, saying that it would be “irresponsible” to do so before reviewing the evidence and findings that would come from a formal inquiry.

“I believe that there are impeachable offenses. That's my view. But my view is not good enough,” Sanders said, citing concerns about obstruction of justice in the Robert Mueller investigation, possible violations of the Constitution’s emoluments clause, and the new allegations around Trump and Ukraine.

“I happen to believe that there are grounds to do it. But you have to lay it out.”

The new tone on impeachment comes after days of reporting about a call Trump had with Ukraine’s president in July that in part concerned Hunter Biden, Joe Biden’s son. On the call, Trump reportedly pressed President Volodymyr Zelensky to investigate Hunter Biden, who had been on the board of a Ukrainian natural gas company while his father was serving as vice president. At the time of the call, which reportedly raised a whistleblower’s alarms, the US was holding back military aid to Ukraine, driving concerns that the aid was being used as leverage in Trump’s bid to hurt a political rival. Trump on Tuesday acknowledged that he directed the aid to be withheld, but told reporters he did so because he wanted Europe to step up and contribute more.

When asked if he believed Democrats should avoid wading into questions about Hunter Biden — like when he told voters during a 2016 debate that he’d rather talk about the issues facing Americans than Hillary Clinton’s “damn emails” — Sanders said only he didn’t know enough about the subject to comment.

“I know I’m a little bit old-fashioned. I like to see the evidence before I talk about things. I read the papers and I read what I read,” said Sanders. “But I don’t know that I know enough at this point to make any definitive statement."

Sanders, 78, made the remarks at a previously scheduled press conference where he was slated to talk about his workplace democracy platform. The event, held at a small lodge in Davenport, Iowa, was the fifth stop of a two-day “Bernie Beats Trump” tour through counties that voted for Barack Obama in 2008 and 2016 before flipping to Trump.

Sanders has been more hesitant than some of his rivals on impeachment, expressing concerns about whether House Democrats should proceed with an impeachment vote when Republicans, he says, would back Trump regardless of what an inquiry might find.

“Here’s the dilemma that you have,” Sanders told reporters on Tuesday. “Now I don’t know — I’ll tell you that my gut is that the average Republican in the Senate and the House is totally intimidated by President Trump. And at this particular point, I have my doubts, like you all. I have my doubts that any Republican, or very few, would vote against him.”

“My fear,” Sanders said, is that if an impeachment vote failed in the Republican-controlled Senate, where it would need two-thirds support to pass, “I know and you know what [Trump] will do: ‘I am vindicated! … I am vindicated!’ And I think that is a fact that has to be taken into consideration.”

“But what do you do when you have a president who has acted in an unconstitutional way? If that is the findings,” Sanders added. “Again, I don’t want to judge it. I think that is the face. But there is a process that has to take place.”

In late May, after the release of Robert Mueller’s report into Russian interference in the 2016 election, Sanders said, “it may be time at least to begin the process through the Judiciary Committee to determine whether or not there are impeachment proceedings.” When addressing the subject, on Tuesday and at past events, Sanders is careful to stress that he supports impeachment inquiries — though not necessarily impeachment itself — “to determine whether or not Trump has committed impeachable offenses,” as he put it at a campaign rally in Nevada this summer.

He has also suggested that Trump might want to be impeached because he knows it’s unlikely he would lose in the Senate. “He may think that it works for him politically,” Sanders said in May.

Other leading Democratic presidential candidates have escalated pressure on congressional Democrats to begin impeachment this week. Elizabeth Warren, who has backed impeachment for months, called Congress “complicit” for not already beginning proceedings against Trump. Kamala Harris, who frequently talks about “prosecuting the case” against Trump in her campaign, tweeted Monday night that “it’s time to impeach.” Biden is scheduled to address reporters Tuesday afternoon and is expected to say Congress “has no choice but to impeach” if the president does not comply with Congress’ requests for information related to the Ukraine call and other investigations.

Already this week, a wave of House Democrats have come out in support of impeaching Trump, including first-year Democrats who won in Republican districts last fall. House Speaker Nancy Pelosi is expected to make a statement on impeachment later Tuesday evening, after meetings with other senior House Democrats.

