In the November general election, Chandler faces Republican Andy Barr in a re-match of the 2010 race, which Chandler narrowly won. Within hours of the release of the Supreme Court decision, the National Republican Congressional Committee issued a statement urging Chandler's ouster.

"In order to regain control of their health care, Bluegrass State families must replace Ben Chandler," it said.

Barr later released a statement noting that Chandler voted against repealing the Affordable Care Act.

"This decision means that the only way to stop Obamacare is to defeat politicians like Ben Chandler who have voted against repeal of this disaster for working families," he said.

Justin Wedeking, an assistant professor of political science at the University of Kentucky, said he doubted Thursday's decision would affect the outcome of the 6th Congressional District race, which includes Fayette County and much of Central Kentucky. The race promises to be one of the most-watched in the state.

"It likely won't affect Chandler's base support," Wedeking said. "His position is already well staked out."

However, if enough new voters who are disappointed with the Supreme Court ruling turn out in November, that could help Barr, he said.

"Surges in turnout generally help challengers," Wedeking said.

U.S. Rep. John Yarmuth, D-Louisville, was the only member of Kentucky's federal delegation to vote for the 2010 bill. He praised the ruling Thursday, saying it would mean lower health care costs for all Kentuckians.

"The law lowers costs, strengthens care and once fully implemented will guarantee all Americans access to quality, affordable coverage while creating nearly 6 million new jobs in the health care sector," Yarmuth said.