Sen. Mitt Romney (R-Utah) sealed a place in history Wednesday when he voted to convict President Trump of abuse of power, becoming a rare lone voice in a Republican Party that otherwise has marched in lockstep with the president throughout the impeachment proceedings.

Romney voted against the second article of impeachment, which accused the president of obstruction of Congress. But on the first article, the Utah senator said in a telephone interview that he found the evidence against Trump overwhelming and the arguments by the president’s defense ultimately unconvincing.

“There’s no question that the president asked a foreign power to investigate his political foe,” Romney said ahead of the floor statement he delivered Wednesday. “That he did so for a political purpose, and that he pressured Ukraine to get them to do help or to lead in this effort. My own view is that there’s not much I can think of that would be a more egregious assault on our Constitution than trying to corrupt an election to maintain power. And that’s what the president did.”

Romney said his decision to vote to convict the president was “the hardest decision” he has ever had to make and one that he hoped he would never have to make. “When [House Speaker] Nancy Pelosi indicated we’re now going to pursue impeachment, my heart sank in dread,” he said.

For a time, he thought — or at least hoped — that Trump’s request to Ukrainian President Volodymyr Zelensky for an investigation into former vice president Joe Biden and his son, Hunter, during a July 25 phone call represented little more than a throwaway line. As more information came out, Romney came to a different and more worrisome conclusion: that the president had committed a potentially impeachable act.

Romney has been a vocal critic of Trump since the 2016 campaign and has been an outlier within the party when it comes to the president’s behavior. But as a loyal Republican who was his party’s 2012 nominee for president, Romney found himself caught between fidelity to party and his own conscience.

“He’s the leader of my party,” Romney said of Trump. “He’s the president of the United States. I voted with him 80 percent of the time. I agree with his economic policies and a lot of other policies. And yet he did something which was grievously wrong. And to say, well, you know, because I’m on his team and I agree with him most of the time, that I should then assent to a political motive, would be a real stain on our constitutional democracy.”

Romney said he hoped the president’s defense team would present evidence during the trial that would exonerate the president. He said he even contacted the White House Counsel’s Office, through a fellow senator, asking if they would provide affidavits from officials such as former national security adviser John Bolton or acting White House chief of staff Mick Mulvaney, but to no avail.

“I was hoping beyond hope that the defense would present evidence, exculpatory evidence, that would remove from me the responsibility to vote where my conscience was telling me I had to vote,” he said. “And that’s one of the reasons, by the way, that I wanted to hear from Bolton, which is I hoped he would testify and raise reasonable doubt.”

Romney dismissed arguments that a president could be impeached only if there were a statutory crime, calling that “absurd on its face,” and saying he could not think of “a more egregious assault on our constitutional system than corrupting an election and getting a foreign power to do it for you.” What Trump tried to do, he said, is “what autocrats do in tinhorn countries.”

He also dismissed the arguments that the president was justified in asking Ukraine to investigate the Bidens. He said the former vice president might have been guilty of a conflict of interest, but added that a conflict of interest is “a matter of judgment, but it’s not a crime.” As for Hunter Biden, he said, “He got a lot of money for his father’s name. That’s unsavory. But again, it’s not a crime.”

Romney said he voted against the article charging the president with obstruction of Congress, despite acknowledging that Trump threw up “a barrage of efforts” to keep the House from receiving documents or testimony from key administration officials with firsthand knowledge. “I don’t think that was an appropriate approach, necessarily,” he said, “but [Trump] did follow the law, and the House did not take the time to go to the courts as I think they should have.”

Some of Romney’s Republican colleagues have suggested that the issue should be left to the voters in this year’s election, rather than having the Senate render judgment. Romney said his reading of the Constitution and the Federalist Papers led him to conclude that the Senate must make the decision.

“The Constitution doesn’t say that if the president did something terribly wrong, let the people decide in the next election what should happen,” he said. “It says if the president does something terribly wrong, the Senate shall try him. And so the Constitution is plain.”

Romney said he made his decision knowing that the president would be acquitted by the Senate. Were mine the deciding vote” to remove Trump from office, he said, “I hope I would have the strength of character to cast that vote. That would be the right thing to do.” He added at another point, “No one wants to vote to remove a president of the United States, and I sure don’t.”

Romney said the question of Trump’s fate now will go be decided in the November election. “It’s going to go to the people, and they will make the final decision,” he said, adding that he is “highly confident” the president will be reelected. “Given the strength of the economy and the record established so far, I believe he gets reelected. And I think if they [Democrats] nominate [Sen.] Bernie [Sanders of Vermont] or [Sen.] Elizabeth [Warren of Massachusetts], he’ll get elected in a landslide.”

Romney also knows that his vote to remove the president from office will bring consequences. Already there is a bill in the Utah legislature that would allow voters to remove a sitting senator. He expects worse in the days ahead.

The president’s son, Donald Trump Jr., attacked Romney after he made his announcement and called form him to be expelled from the Republican Party.

“Mitt Romney is forever bitter that he will never be POTUS. He was too weak to beat the Democrats then so he’s joining them now,” Trump Jr. wrote on Twitter. “He’s now officially a member of the resistance & should be expelled from the @GOP.”

Romney had already received a taste of what he is in for ahead of his public announcement but after he voted to hear more evidence in the trial.

When he was in Florida last weekend, a person at the airport called him a traitor, and someone else later told him to “get with the team,” followed by an epithet. “It’s going to be there a long, long, long time,” he said. “And you know, the president’s going to, you know, use me in rallies. I mean, he likes theater, and I can be part of that. So it’s going to be tough.”

He added: “But again, how do I say before God, ‘I agreed to render impartial justice and let the consequences for me personally outweigh my duty to God and my duty to be to the country that I love?’ And that’s simply putting my head down and saying what was done was perfect, there’s nothing to see here was not something I could do.”

Asked how well prepared he is for the attacks he knows will come, he said, “Not very well prepared. I have tried to keep myself from really thinking about that so that I didn’t lose my resolve.” He recalled a hymn he has sung in church that he said says to do the right thing and let the consequences follow. “I’m only dealing with the first part. . . . And I know there will be consequences.”