In the 1950s, the Republican Party stood by Sen. Joseph McCarthy when he alleged conspiracy theories about members of the government being communist allies and spies without proper evidence. It eventually became the consensus of the voting public that McCarthy and the Republicans were in the wrong. In the 1954 elections, the Grand Old Party, which at that time controlled the Senate and House (and the presidency), lost two seats in the Senate and 19 seats in the House, flipping control of both chambers to Democrats.
In the 1970s, the Republican Party stood by President Richard Nixon when he gave unethical orders to fire executive-branch officials investigating the Watergate break-in/cover-up and when he defied congressional subpoenas. It eventually became the consensus of the voting public that Nixon and the Republicans were in the wrong. In the 1974 elections, the GOP lost four seats in the Senate and 49 seats in the House — giving rare supermajorities in both chambers to Democrats. Democrat Jimmy Carter won the presidency in 1976.
Did Republicans get any lasting benefits from their willingness to go down with the sinking ships of McCarthy and Nixon? Do we honestly believe our loyalty to Donald Trump will be different?