Will the establishment learn?

The Weekly Standard asks the question after Thad Cochran barely made it across the finish line - why did so many loyal Republicans vote against him?
Establishment politicos often act superciliously toward these challengers, but in so doing they are missing a profound point: The Republican electorate is exceedingly angry and frustrated with their leadership. The fact that these second- or third-raters can give established leaders such a scare is proof positive. The party’s leadership can snicker at these challengers all it wants, but it had better understand that its own voters are so fed up with them that they are using these deeply flawed candidates to send them a message.
If we keep banging on the door, it will break down.