Now 10 Republican Yeas.
As someone remarked, the most bipartisan presidential impeachment in US history.
Well, aside from the very-far-from-insignificant matter of Trump being a dangerous idiot who may well also soon be a criminal....
.... there are three other systemic reasons why
this should be the case.
The first is that in six days Trump is going to be out of office and a very long way away from the levers of power - not just within the federal government, but also (importantly) within the GOP. This means that House members of the President's colour have absolutely nothing to lose, and arguably quite a lot to gain, by voting against his impeachment. In all previous presidential impeachments, the president in question a) still had at least a year left in office*, and b) still had significant power and standing within his own party.
The second (IMO) is that the Republican party machine (including GOP representatives and senators) are mad as hell at Trump managing to wreck what should have been a Republican Senate majority, since it's generally agreed by pretty much everyone that the only way the Georgia elections went the way of the Democrats was on account of Trump's words and actions in the wake of the Pres Election. Trump can therefore be viewed as the one person who singlehandedly dismantled the only lever of power the GOP was going to have for the next four years.
The third (IMO) is the very personal factor related to last week's Capitol riot. Not only did congresspeople and senators have to watch (from a designated safe area) as their place of work - and a building which has such deep resonance as a hallmark of American values - was violated, many of them came away with genuine emotional trauma.
Of course, the thing of real interest (given that the House was always going to impeach, regardless of how much Republican support there was) is 1) when will the Senate trial take place, and 2) are there at least 17 GOP senators who are prepared to cross the floor? To me, it looks likely now that when the Senate reconvenes, it will schedule the trial for some time in April/May, for two reasons: first, this will give time and space for Biden to get his new team through the Senate confirmation hearings, and it will give Biden and his team the ability to pass new legislation through Congress; and second, I suspect that even in the current climate wrt Trump, senior Democrats and Senate leaders will judge that the next few months really should see Congress focussing very strongly on the Covid situation and its many ramifications. And after all, Trump will be out of office and effectively harmless (in purely political terms) after Jan 20th.
* Technically, the Andrew Johnson impeachment happened with 9 months left to run in his presidency, but in fact the impeachment process - which turned out to be messy and complicated - had begun the previous year.