Not quite as much as some of his fans suggest, writes Bill Scher:

What about O’Rourke’s down-ballot coattails? Wasn’t he able to juice Democratic base turnout so much that Democrats flipped two U.S. House seats, two state Senate seats and 12 state House seats?
Let’s not be so quick to give Beto all the credit. All those red-to-blue wins were on urban-suburban turf, the same kind of turf that was fertile for Democrats nationwide. The two U.S. House seat flips in Texas were in districts that Clinton won, districts already primed to turn blue.
Outside Texas, other, less viral Democrats were able to win U.S. House seats in more challenging territory, such as Oklahoma’s 5th District and South Carolina’s 1st District. And Democrats flipped 380 state legislative seats nationwide, including 10 state House and six state Senate seats in North Carolina, and seven state House seats in Iowa—both swing states that went to Trump. No electrifying progressive superstar was at the top of the ticket in any of those four states.