[AnthonyMouse]

> It is clear that a person appointed by a red governor cannot represent the blue governor who administers the purple state for several years starting six months later.

The purpose of the Senate isn't to represent the existing representatives in a state, it's to represent the interests of the state in the abstract. Having a red US Senator in a state with a blue Governor is no more a problem than having a red state legislature in a state with a blue Governor.

> But since American separation of powers prefers to give legislative power to the executive, it's less obvious that making governors members of the Senate is repugnant.

This is largely only true at the federal level and for a very specific reason. The federal government was not structured for the level of responsibility it has taken on as a result of the direct election of Senators removing the state veto on increasing federal scope.

In state governments you have an elected governor and legislature, but also elected school boards, treasurers, sheriffs etc. There are no elected positions in the Federal Department of Education, nor the Federal Reserve, nor the FBI. The constitution didn't contemplate that the federal government would grow to cover so many things, so they all fall under executive control. But the source of the problem isn't pushing too many things to the executive, it's pushing too many things to the federal government to begin with.