Despite the overwhelming evidence that Donald Trump has committed impeachable offenses, it is still extremely unlikely that he will be convicted in the Senate, which would require 20 Republicans to vote for his removal. This brings up a question: is this a poorly conceived rule? After all, many constitutional provisions were ill-conceived or have stopped working, and the framers were certainly in denial about the formation of political parties, so it wouldn’t be surprising if they got this wrong.
But, in this case, I would say that a supermajority requirement to remove the president is probably better than a simple majority alternative. There is ultimately no institutional rule that can effectively deal with a major party that doesn’t accept the legitimacy of the opposition party and will take an LOL Nothing Matters stance to any malfesance on the party of a co-partisan president (with the possible exception of vetoing tax cut bills.) A simple majority conviction rule would just replace false negatives with false positives, which would probably be even worse. To put it another way, Trump would probably still be safe with a simple majority conviction rule, but we might have ended up with President Paul Ryan sometime in Summer 2015.
Where the framers can be blamed for this is that their anti-democratic impulses (inter alia) led a majority of them to create the Senate and Electoral College, which make an LOL Nothing Matters minority faction much more viable as an aspirant for national offices than it would be under a more democratic electoral and legislative structure. I’ve been using the quote from Federalist 68 cited above in my presidency class for a decade; for some reason, starting in 2017 students started laughing whenever the slide comes up. I wonder what can explain it.