The reality of politics today, is that anything Democrats do overseas is “off-limits”, and anyone looking into their overseas criminal activity is somehow colluding with a foreign government.
Anything Republicans do overseas is immediately defined as collusion and treason, must be investigated as Democrats see fit, and the Republican must be tried and convicted even if no crime occurred at all.
You nailed it, and that’s why Republicans do as they are told or sit in the corner quietly.
Times have changed. In my 1960s era high school classes we were taught that in spite of political differences, we were all Americans, and "Politics Stops At The Water's Edge".