Even in the unlikely event that anti-Trump activists were able to round up the 37 electors required to deny Trump a winning 270 vote threshold, that would merely throw the election to the House of Representatives, which will be controlled by Republicans, who would likely install Trump anyhow. They would become more directly accountable for their decision to enable Trump in the first place, and Trump’s administration would rightly be further tainted. But he would become president.
Should a House controlled by the same party as the person who won 270-plus electoral votes worth of states be unable to install that person into the presidency, it would be a history-making event, but it would also be evidence on its face that the “winner” was too great a threat to our system of government to be allowed to take office. His own party would have rejected him. This is impossible to imagine happening in an environment where his Republican vice president, the Republican Speaker of the House and the overwhelming majority of Republicans in the country support Trump.
To the extent that what’s under consideration would be the greatest show of Electoral College rebelliousness in U.S. history, it would be unprecedented. But the assumption that it would be corrosive to norms doesn’t follow from there. Unprecedented use of constitutional powers can firm up important norms, and in this case it would serve as a reminder to future presidential candidates: Yes, you might be able to win by violating all of the courtesies and standards our political system takes for granted, but even if you do, your presidency will run its course under a cloud. Impeachment is an important power until such time as it turns into a routine partisan cudgel. This is no different.