They also have to find enough success stories — people who have gotten their health coverage and are pleased by the experience — to counteract the comments Republicans are circulating from people who are complaining that the premiums are too high. There are people who are successfully signing up, on the federal website as well as state-run marketplaces like the one in Minnesota. But they haven’t been able to overshadow the stories of people who can’t even log in.

“Since at the end of the day, Obamacare is a marathon and not a sprint, the president and Democrats are well positioned,” said Democratic strategist Chris Lehane. But the only way to make the marathon shorter, Lehane said, is for the administration to be effective in telling the success stories.

That will be especially important for four red-state Democratic senators — Mark Pryor of Arkansas, Mary Landrieu of Louisiana, Kay Hagan of North Carolina, and Mark Begich of Alaska — who are up for re-election next year and will need ammunition to counter Republican attacks on the law. So far, they’ve stayed silent on the implementation problems — but none of them broke ranks with Democratic leaders in the fight against the GOP Obamacare defunding and delay efforts.