On December 17, four Republican members of the U.S. House broke with their own party and signed the discharge petition so that the House can vote on extending Obamacare premium subsidies. See this story. The four include three Pennsylvanians and one New Yorker. They are Brian Fitzpatrick, Rob Bresnahan, Ryan Mackenzie, and Mike Lawler.
All four congressmembers are from states with closed primaries.
Over and over, opponents of closed primaries preach that closed primaries produce extremist politicians.