While Washington is obsessing over what the results of Missouri’s anti-health care reform ballot initiative mean for President Barack Obama, the state’s political insiders are debating whether it’s Democratic Senate nominee Robin Carnahan who needs to be worried.

A staggering 71 percent of Show-Me state primary voters cast ballots Tuesday opposing the new federal health care law — a symbolic yet resounding message that places Carnahan on the opposite side of a supermajority of the electorate.

The overwhelming vote in favor of Proposition C, a measure crafted to reject a portion of the law that requires most people to carry health insurance by 2014 or pay a fine, is the first tangible demonstration of how unpopular the president’s signature achievement remains in the Midwestern state...