Americans give Barack Obama mixed marks on three prominent issues he's touted in his bid for re-election, with no scores above 50 percent on the auto industry bailout, greater regulation of financial institutions or - most basic - the administration's economic stimulus program.

Middling ratings on each of these suggest some of the president's challenges in the campaign, now officially under way. While he's substantially more popular personally than the presumptive Republican nominee, Mitt Romney, Obama is vulnerable on key issues.

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This ABC News/Washington Post poll finds that Americans divide almost exactly evenly on the administration's economic stimulus program, with 47 percent seeing it favorably overall, 48 percent unfavorably. It's a bit better for Obama on the auto industry loans, 50-43 percent, and financial industry regulation, 49-44 percent. But none of these reaches majority favorability, and the intensity of sentiment on the stimulus is much more strongly negative than positive.

PARTISANSHIP - Obama has cited his performance on these issues, among others, in making his case for re-election. But this poll, produced for ABC by Langer Research Associates, finds responses sharply divided by political allegiance and ideological preference.

In likely the president's biggest risk, independents rate the economic stimulus negatively by 50-44 percent. They're less negative (indeed slightly positive) on the automaker loans and regulation of financial institutions. But it's the economy that dominates voter concerns. Political independents are the key swing voters in national elections - and at 41 percent of the population, they outnumber Democrats and Republicans alike in this survey, 33 and 23 percent, respectively.

Among partisans, anywhere from 66 to 74 percent of Democrats and liberals have positive views of Obama's work on these issues, compared with a paltry 16 to 26 percent of Republicans and 24 to 35 percent of conservatives. Moderates are more positive than negative on all three, but again most closely on the economic stimulus.

As noted, intensity of sentiment on the stimulus is against the president: Among all Americans, many more rate the economic stimulus strongly unfavorably, 31 percent, as strongly favorably, 18 percent. It's a similar 31 vs. 15 percent among independents. Strong sentiment on the automaker loans and financial industry regulations is more evenly divided.

An ABC/Post poll last month found Obama leading Romney head-to-head in trust to handle six key issues, including international affairs, protecting the middle class and social issues. But, in a result reinforced by this survey, it was 47-43 percent, Romney-Obama, in trust to handle the economy.

Obama's on much better ground in personal popularity, 56-40 percent favorable-unfavorable in a mid-April ABC/Post poll, compared with Mitt Romney's 35-47 percent. But trust on the issues - particularly on the economy - can matter more.

OTHER SPLITS - Obama's handling of the three issues tested in this survey is more popular with elements of his 2008 coalition, including African-Americans, college graduates and young adults.

Among whites and seniors, however, he's numerically underwater or worse, most notably on the economic stimulus. And while Hispanics view his work on these issues favorably, it's only by slight majorities.

While there's a broad gender gap in support for Obama vs. Romney, it's more muted on these policy issues. Women are more apt than men to see the economic stimulus favorably, but by a single-digit gap, 8 percentage points. It's narrower still on the other issues. Were women to focus more on the stimulus than on other issues, Obama's advantage among them could be at risk.

METHODOLOGY - This ABC News/Washington Post poll was conducted by landline and cell phone May 2-6, 2012, among a random national sample of 1,006 adults. Results have a margin of sampling error of 3.5 points. The survey was produced for ABC News by Langer Research Associates of New York, N.Y., with sampling, data collection and tabulation by SSRS/Social Science Research Solutions of Media, Pa.