I don't think it's a given at all.
Good for you - had to say it twice, huh?
If the Senate had 51 Democrats, we would see a Senate trial which was just as much a travesty of justice as Adam Schiff's star chamber proceedings have been...but it would still be hard for the Democrats to get to 67 votes.
As it stands, the legitimacy of our government may depend on 20 individuals not giving in to the blandishments of the Left.