I think it started about half a century before that, but the 17th amendment really gave it steam. If state legislatures were doing the nominating, I can't imagine that even an ultraleft state like Washington would be sending an absolute dunce like Patty Bun Murray to represent them.
You’re right. They’d be sending cretins like Kshama Sawant. Patty bin Murray is too right wing for them. Meanwhile, “right wing” Texas would be sending David DewCrist and Tokyo Rove. Repeal of the 17th is insanity at this point.