There have been a series of RINOs in that seat going back to at least the 1950s -- George Aiken, Bob Stafford, and Jumping Jim. Vermont was one of only two states to vote against FDR in 1936, and was of course home to Calvin Coolidge, so it does have some glory in its distant past. But not much lately.
A RINO from a lefty state is OK.
Now, a RINO from a state that elects conservatives, like Arizona, Nebraska and Penn...they are not tolerable.
Good mention of Coolidge, who is one of the best Presidents of this century. He was one of the last true federalists; he would not involve the federal government in matters that were not outlined to it in the Constitution. Once, there was a major natural castrophe somewhere in the Southwest and the state requested funds from the government; Coolidge said no way; the government had no power to take $$ from one state and send it to another.
Can you imagine any politician saying that today?