Believe it or not, some people actually weigh the evidence and decide things for themselves instead of going with the herd. Sometimes, they size up facts differently. Romney has always done that. I have long agreed with Jonah Goldberg that Mitt Romney speaks conservatism as if he used Rosetta Stone. But Romney unquestionably has always been a man of moral conviction not prone to tribalism.
For those who believe Romney did this for hate, vendetta, personal grievance, ulterior motives, or other nonsense, such conclusions actually say way more about those who have arrived at those conclusions than about Romney. The man realizes the Democrats will be vilifying him on the next vote just as the same Democrats praising him today spent years attacking him.
Romney votes for President Trump’s agenda in the Senate over 78% of the time (over 80% before the impeachment vote). That is higher than Susan Collins, Rand Paul, Mike Lee, or Lisa Murkowski. (Source). He votes more frequently for Donald Trump’s agenda than any Democrat including Joe Manchin and Krysten Sinema. He will vote to put Trump’s judges on the federal bench and you can hate him more knowing he is actually doing exactly what you want, but you’ll be damned if you ever say a nice word about him because of this one vote.