Pastor jumps into crowded primary against Graham
© Greg Nash

A well-connected minister is throwing his hat in the ring against Sen. Lindsey GrahamLindsey GrahamA Cabinet position for Petraeus; disciplinary actions for Broadwell after affair Pentagon should have a civilian chief to give peace a chance Lawmakers eye early exit from Washington MORE (R-S.C.), further crowding the field against the senator.

Pastor Det Bowers (R) will become the fifth primary opponent for Graham, adding a dose of uncertainty into the race.

"No question," Bowers told CNN in a phone interview. "I am definitely running."

Graham is vulnerable on the right on immigration and energy issues, but no top-tier candidate has emerged to challenge him and the senator has a huge $7 million warchest. His four other opponents have struggled with fundraising and name recognition.

But Graham's foes are hopeful the clown-car primary will make it harder for the senator to reach 50 percent in the first round of voting, and that whoever makes it into the runoff with him could give Graham a tough race.

Bowers said he'd attack Graham's support for "amnesty." Graham has taken heat on the right for his work on bipartisan immigration reform legislation.