This isn’t totally right: “Questioning Trump’s legitimacy is basically the birtherism of the left,” said Christopher Buskirk, publisher of American Greatness, a conservative website. “Illegitimacy is just where both left and right are going these days when they lose elections. We don’t have a shared consensus on what the institutions of government should do, and that makes it harder for partisans to accept the outcome of elections.”

Legitimacy in every country that holds elections to pick its political leader comes from high participation in voting, with all votes counted equally, and the winner being the one who gets the most votes.  

That’s why President Trump is right to favor a national vote to choose the president.