Before a crushing primary defeat Tuesday night, Rep. Mark Sanford was already an endangered species: part of that rare breed of fiscal conservatives who opposes growing government even when Republicans are in charge.

When the 1994 “Republican revolution” started to lose steam as the decade wore on, the South Carolina lawmaker continued to push for spending cuts alongside a small group of conservative dissidents. Within five years, he and then-Rep. Tom Coburn, R-Okla., were shutting down a floor debate on an overstuffed appropriations bill in defiance of GOP leadership.