WASHINGTON – Sen. Jim DeMint, patron saint of the tea party and a would-be Republican kingmaker, announced suddenly Thursday he would resign his South Carolina seat to head Washington’s conservative Heritage Foundation think tank, a shift that reverberated through a soul-searching GOP.

Just two years into a second, six-year term, DeMint said he would step down Jan. 1 to helm Heritage while continuing the conservative fight. The 61-year-old lawmaker, known to hurry home to South Carolina nearly every weekend, had signaled that this term would be his last, but his abrupt announcement shocked even his closest Republican colleagues.

“When he told me this morning, I about fell off my couch,” said South Carolina’s other senator, Republican Lindsey Graham. “I didn’t see this coming.”