One poll does not a trend make, but Gallup has some good news for President Obama: Its first poll on healthcare reform since Congress passed legislation late Sunday shows nearly half the American public approving.

Some 49 percent of American adults called the new law “a good thing,” compared with 40 percent who called it a “bad thing.”

Two weeks before the congressional vote, Gallup found 45 percent of Americans favored passage and 48 percent opposed.

In the latest results, Gallup sees “a clear political victory” for Mr. Obama and his allies in Congress. Gallup also notes the wide disparity in partisan reactions, with 82 percent of Democrats either “enthusiastic” or “pleased” and 79 percent of Republicans either “angry” or “disappointed.”

“Whether these groups’ views on the issue harden or soften in the coming months could be crucial to how healthcare reform factors into this year’s midterm elections,” writes Lydia Saad of Gallup.

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Gary Langer, director of polling at ABC News, says the Gallup result means that a “winner’s bounce” is possible, but he needs more data to know.

A poll released Tuesday by Bloomberg showed no such bounce. The survey found 38 percent of Americans favored the healthcare overhaul versus 50 percent who opposed it. The poll was conducted both before and after the House vote, between March 19 and 22, though the polling firm found no meaningful movement of opinion after the bill had passed.

As always, the wording of the questions could have affected the outcome. In the Bloomberg National Poll, conducted by Selzer & Co., respondents were asked whether they “favor or oppose the healthcare overhaul plan.”

“Anything called a ‘massive overhaul’ will be complicated, and it is hard for people to see what is in it for them,” J. Ann Selzer, president of Selzer & Co. in Des Moines, Iowa, told Bloomberg News. “Even as Americans of all stripes agree there are problems with the current system, the escalating deficit makes them worry what the country can really afford.”

In the Gallup question, the healthcare bill was described as one that “restructures the nation’s healthcare system.”

On Thursday, Obama heads to the University of Iowa, in Iowa City, for a speech on the new healthcare law, a signal that the White House knows it still has some selling to do. Iowa City is a heavily Democratic part of the state, and Obama used it as a regular backdrop during his presidential campaign. His victory in the Iowa caucuses, the first nominating contest in 2008, helped propel him to his party’s nomination.

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