Mitt Romney said:

The allegations made in the articles of impeachment are very serious. As a senator-juror, I swore an oath before God to exercise impartial justice. I am profoundly religious. My faith is at the heart of who I am. I take an oath before God as enormously consequential. I knew from the outset that being tasked with judging the president, the leader of my own party, would be the most difficult decision I have ever faced. I was not wrong….

The historic meaning of the words “high crimes and misdemeanors,” the writings of the founders and my own reasoned judgment convince me that a president can indeed commit acts against the public trust that are so egregious that while they’re not statutory crimes, they would demand removal from office. To maintain that the lack of a codified and comprehensive list of all the outrageous acts that a president might conceivably commit renders Congress powerless to remove such a president defies reason….

Given that in neither the case of the father nor the son was any evidence presented by the president’s counsel that a crime had been committed, the president’s insistence that they be investigated by the Ukrainians is hard to explain other than as a political pursuit. There’s no question in my mind that were their names not Biden, the president would never have done what he did….

The defense argues that the Senate should leave the impeachment decision to the voters. While that logic is appealing to our democratic instincts, it is inconsistent with the Constitution’s requirement that the Senate, not the voters, try the president….

The grave question the Constitution tasked senators to answer is whether the president committed an act so extreme and egregious that it rises to the level of a high crime and misdemeanor. Yes, he did.

The president asked a foreign government to investigate his political rival. The president withheld vital military funds from that government to press it to do so. The president delayed funds for an American ally at war with Russian invaders. The president’s purpose was personal and political. Accordingly, the president is guilty of an appalling abuse of public trust.

What he did was not perfect. No, it was a flagrant assault on our electoral rights, our national security and our fundamental values. Corrupting an election to keep oneself in office is perhaps the most abusive and destructive violation of one’s oath of office that I can imagine.