"But, my job is to try to win as often as I can in the Senate. There's always the next vote," McConnell said. "Senator Romney on the whole has been supportive of what we've been trying to accomplish in the year that he's been there."

"I think this was a mistake," McConnell continued. "I disagree with it. On the other hand, we've got a lot more votes to cast between now and November and I'm going to need his support on a whole variety of things that are important to the president and to the country."

Romney shocked his colleagues when he announced less than two hours before the votes on the two House-passed articles of impeachment that he would vote to convict Trump of abuse of power in his decision to delay roughly $391 million in Ukraine aid allegedly in exchange for the country launching politically motivated investigations.

“The grave question the Constitution tasks 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 is guilty of an appalling abuse of public trust,” Romney said during an emotional Senate floor speech.

Romney's decision robbed Republicans and the White House of what they had been telegraphing as their key takeaway from the impeachment trial: that Republicans would unanimously unite to acquit Trump while Democrats would likely lose a few votes.

Instead, every Democrat voted to convict Trump on both abuse of power and obstruction of Congress, though both articles fell short of the two-thirds necessary to remove the president from office. Romney joined every other Republican to vote to acquit Trump on the obstruction of Congress charge.

After the vote Trump released a video that characterized Romney as "slick, slippery [and] stealthy." Meanwhile, top allies of Trump's immediately called for retribution against Romney, including Donald Trump Jr. calling for the Utah senator to be removed from the party.

However, GOP senators quickly quashed any talk of Romney being removed from the conference or getting a formal reprimand for breaking ranks on the impeachment vote.

With a narrow 53-seat majority, Romney's vote is crucial for Republicans.

McConnell indicated to reporters earlier that he was ready to move on, and when asked how long Romney would be in the doghouse, the GOP leader laughed.

"We don't have any doghouses here," he said. "The most important vote is the next vote."

Updated at 10:28 p.m.