Sen. Lindsey GrahamLindsey Olin GrahamOvernight Cybersecurity: Senators eye path forward on election security bill | Facebook isn't winning over privacy advocates | New hacks target health care Paul backs Pompeo, clearing path for confirmation Can Silicon Valley expect European-style regulation here at home? MORE (R-S.C.) said during the first and only debate of the South Carolina Republican Senate primary that he would “beat the Democratic candidate’s brains out” if he wins renomination on Tuesday, as is widely expected.

Graham is facing six primary challengers, none of whom have picked up much steam. The most recent survey of the race, conducted at the end of May, showed Graham just under the 50 percent threshold needed to avoid a runoff, but he’s expected to top that number on Tuesday.

That didn’t prevent his challengers from taking aggressive shots at him during the Saturday night debate, however. All hit similar themes, slamming Graham for what they said was too much cooperation with Democrats and emphasizing their belief that he’s been in Washington too long.

State Sen. Lee Bright, seen as the likely second-place finisher, said it “would be a catastrophe for this nation” to send Graham back to Washington, and touted himself as a Republican in the same tradition as former South Carolina Sen. Jim DeMint, who was known for his staunch opposition to legislation he saw as not conservative enough.

Businessman Richard Cash blasted Graham for working with Democrats.

"It doesn't matter if you get something done if you're doing the wrong thing," Cash said.

But Graham defended his efforts to push through compromises, declaring that immigration reform “is not a problem that is going to get fixed by yelling about it.”

While Graham was seen as one of the top targets for the Tea Party this cycle, he’s managed to fend off a serious challenge through a combination of hefty fundraising and shrewd political maneuvering in the Senate. 

His expected win has been seen as another show of strength by the establishment over the Tea Party. But at least one candidate, businesswoman Nancy Mace, pushed back on that narrative Saturday night.

"This is not a referendum on the core of the Republican Party," Mace said. "It is a referendum on Washington."

But Bright embraced that theme, coming off of an invigorating success for the Tea Party in Mississippi, where conservative challenger Chris McDaniel has forced Sen. Thad Cochran (R) to a primary runoff.

"The rest of the nation is looking at us," Bright said. "Is South Carolina going to make its stand?"

In Mississippi, Republicans see Cochran as a much stronger candidate in the general election, and believe if McDaniel is nominated he could give Democrats a shot at the seat. 

Such an outcome is far less likely in South Carolina, but Graham touted his strength in a general election as part of his appeal, noting that Tea Party-backed candidates had lost winnable races in previous cycles.

In contrast, “I’ll beat the Democratic candidate’s brains out,” Graham said. “They know it. They’re not going to going to spend 15 cents here.”