Foster is challenging Republican U.S. Rep. Tom Graves in the northwest Georgia district, a deep-red bastion where Democrats have struggled to gain traction.
He was jailed Monday after a jury convicted him of driving under the influence, a misdemeanor violation until the fourth offense. A sentencing hearing is scheduled for next week, and Foster could face possible prison time of 10 days to a year.
Foster, 61, has been investigated by the U.S. Army on allegations he stole surplus military boats to deliver humanitarian aid. Honduran police charged four of his charitable group's employees with cocaine trafficking.
And he has been stripped of his Georgia medical license and slapped with hundreds of thousands of dollars in local, state and federal tax liens. He now owns the site of an "adults only, clothing-optional lifestyle retreat" in North Georgia.
After he was stopped by police in September 2017, Foster encouraged them to record his statements so he could later get a copy of the footage. He requested his blood samples be sent to CIA headquarters and said he was unfazed by the threat of prison.
"Go right ahead, I've had them pinched before by Colombian police," Foster tells the arresting officer as he was handcuffed, according to the newspaper. "It's all right, I've been in jail in six damn countries and the state of Mississippi."
It's not immediately certain whether he'll remain on the ticket. Dan Lovingwood, the chair of the Democratic 14th Congressional District, told the Daily Citizen-News that Foster is unlikely to step down.
"He would not have taken this to trial if he had thought he would be found guilty,” said Lovingwood. “I have no comment to make other than that. He's still in the race. He seems more determined than ever to continue.”