Jimmy Carter doomed universal health care in the 70s. He promised it when he ran for president in 1976, but then his administration dithered and delayed, worried about the costs, proposing incrementalism instead. Ultimately, Senator Ted Kennedy, author of his own universal health care bill, got so tired of the delays, backtracking, and broken promises that he ran a primary challenge against Carter in 1980, which failed but may have doomed Carter's chances in the general election.

Carter ran as an outsider, and his problem as President is that he was an outsider, alienating his own party, making him largely ineffectively, and leaving him with no base of support anywhere.

Democrats could have passed universal health care when they had a filibuster-proof super-majority near the beginning of the Obama administration, but Obama himself was kind of an outsider and quite a political novice, having served less than one term as Senator. It's a joke to call it "Obamacare", because Harry Reid and Nancy Pelosi did practically all of the negotiating and heavy lifting, while Obama himself was mostly MIA during the debate. (Not to mention, the Obama administration completely botched the ACA rollout.) And the Democrats bent over backwards to water down the proposals to get Republican votes, but they ended up getting precisely zero Republican votes anyway, despite the fact that their bill was basically Romneycare.