Roy Moore's win in Alabama shows the bankruptcy of the establishment GOP
A better question is, why would anyone have voted for Luther Strange?
Strange stood as an avatar for two things: A Republican political establishment in Alabama, and one in Washington, neither of which has much to offer voters.
On the national level, what have Majority Leader Mitch McConnell and the Republican Senate conference produced for Republican voters? They have not repealed Obamacare. They have not cut taxes. Their primary accomplishment is rubber-stamping a Supreme Court nominee from the president.
McConnell is comically unpopular. People tend to talk about that as a reflection of the Trumpification of the Republican Party, but what reason is there for Republicans to like McConnell, given how little he has delivered? And why would they have chosen the candidate a McConnell-linked PAC spent millions to prop up?
On the state level, Strange was Alabama's attorney general before he was appointed to the Senate. Then-Gov. Robert Bentley appointed Strange to the Senate while Strange's office was conducting an investigation that would eventually lead to Bentley's resignation.
There was wide suspicion that this was a corrupt deal - especially because Strange had asked the state legislature to hold off its own investigation into Bentley.
There is a tendency for national observers to overrate national factors when evaluating state races. But Alabama's Republican establishment is especially troubled - beyond Bentley, who pleaded guilty to two misdemeanors as part of a deal to resign, a Republican State House Speaker was convicted of felony ethics violations last year.
Given all these factors, it's hard to figure out what the case for Strange was, besides "he's not crazy like Roy Moore."
As we saw in 2016, "my opponent is unacceptable" isn't necessarily a winning argument, in a primary or a general election.