Make Congressional Representatives Less Parochial

A few years ago, this idea came to me that the US, collectively, might get a better Congress if it were less parochial. My proposal was that some fraction of Congress should be elected by randomly assigned national constituencies.

I have a refinement, or alternative, to that idea. I would like to see some fraction of each member to be elected by a randomly assigned national constituency. Off the top of my head, 20% national constituency seems like a good number.

That would preserve local representation, while introducing a national constituency large enough to be a powerful tie-breaker.