Democrats who have been expecting a tough slog to defend the implementation of Obamacare in this important midterm election year weren't just pleased this week with news that 7.1 million people had enrolled in health insurance through federal or state exchanges.

They were jubilant, and more than a little relieved.

"The Affordable Care Act CRUSHED its first major enrollment deadline!" a fundraising email on behalf of the Democratic Congressional Campaign Committee declared Wednesday.

Such caps-lock, exclamatory enthusiasm is reflective of a brightening mood this week among Democrats, who understand that many of their candidates could win or lose this year on the merits of the health care law and its first-year implementation. And for a party that has suffered a long political winter, the creep of cautious optimism is a welcome warming trend.

"This is a new political environment where implementation of law is going well. That's a much better political environment for us," said Matt Canter, Democratic Senatorial Campaign Committee deputy executive director.

Democrats have for months touted some changes brought about by the health care law, including increased access to birth control and health coverage for people with pre-existing conditions. But those facets of the law and others have been largely obscured by the uneven début of the website and sudden, unilateral delays to some parts of the law by the White House. Republicans have latched on to the law's problems in frequent political attacks, and public support for the Affordable Care Act and the president have plummeted in kind.

But, with a trickle of positive news about the health care law, public opinion appears to be slightly on the uptick. A recent ABC News/Washington Post poll showed 49 percent of people in support of Obamacare -- the highest measure ever for that survey.

That's not nearly enough to make the health care law a positive factor politically, and the National Republican Senatorial Committee pointed out that the president was not joined by any Democratic lawmakers during his announcement Tuesday, nor were vulnerable Democratic candidates vocally lauding the enrollment news. (Rep. Gary Peters, the Democratic candidate for Senate in Michigan, did appear with President Obama in Michigan on Wednesday, however.)

Rep. Steve Israel, who chairs the Democratic Congressional Campaign Committee, cautioned during a news conference Wednesday that it is "too early to say whether the tide has turned" on Obamacare as a political issue. But Israel, who must decide how to shield House Democratic candidates from some of the law’s potential landmines, is confident the outlook for Democrats will improve eventually.

“I think the climate will change on the Affordable Care Act,” he said.

Israel pointed to the government shutdown last year, during which congressional Republicans bore the brunt of blame from the American public, and some pundits predicted the party could be putting its House majority in jeopardy. Then, just a few weeks later, the rocky rollout of turned the political tables.

“If three weeks made such a dramatic difference in the climate,” Israel said, “who knows what the next seven months will bring?”