Barack Obama may get no more than a gentleman's C for the way he's running his presidential campaign - but that beats Mitt Romney, whose effort is seen more negatively than positively by the American public, with notably softer ratings for Romney in his base than for Obama in his.

After a week in which Romney has struggled to counter questions about his tax records and his tenure at Bain Capital, just 38 percent of Americans in this ABC News/Washington Post poll express a favorable opinion of the way he's running his campaign for the presidency, while 49 percent respond unfavorably - an 11-point negative margin.

See PDF with full results, charts and tables here.

Obama, for his part, gets an even split in assessments of his campaign efforts, 46-45 percent, favorable-unfavorable, in this poll, produced for ABC by Langer Research Associates. (Nine percent are undecided about the way Obama's handling his campaign, vs. a bit more, 14 percent, on Romney's efforts.)

With the race so close - the pair were precisely tied in an ABC/Post poll last week - views of their effectiveness running their campaigns can matter. So, of course, will the campaigns themselves, particularly if the race comes to down to motivating and turning out base supporters.

Indeed, part of the difference is in the candidates' core support groups. Seventy-five percent of Democrats have a favorable opinion of Obama's campaign management; fewer Republicans, 66 percent, rate Romney's campaign positively. And that gap widens by strength of sentiment: Forty-three percent of Democrats hold a "strongly" favorable opinion of Obama's campaign efforts. Many fewer Republicans, 28 percent, see Romney's work on his campaign strongly favorably.

Among independents, 47 percent rate Obama's campaign positively, as do 41 percent for Romney's, with more undecided, rather than negative, on Romney. "Strongly" favorable views among independents are quite low for both candidates, but tilt more toward Obama's campaign performance, 17 percent, vs. Romney's, 10 percent.

STATES - These partisan differences are reflected among states. People in states rated by the ABC News Political Unit as favoring or leaning toward Obama view his campaign efforts positively by a 12-point margin, 51-39 percent. In states seen as favoring or leaning toward Romney, his campaign ratings are more evenly divided, 45-43 percent, favorable-unfavorable.

In toss-up states there's a 44-49 percent split on how Obama is handling his campaign, 38-48 percent on Romney.

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GROUPS - There are other differences among groups. Obama's campaign efforts are viewed negatively rather than positively by whites by a 22-point margin, 34-56 percent, favorable-unfavorable, while positively by nonwhites by a vast 51 percentage points, 72-21 percent.

Romney's campaign gets about an even split among whites - hardly an inspiring score - and a broadly negative rating among nonwhites.

Obama's campaign is rated 8 points more positively by women (who are more apt to be Democrats) than by men; and less negatively by under-40s, while much more negatively among seniors. Romney, for his part, gets an especially negative score among 50- to 64-year-olds.

There's also a sharp division among college graduates: They're positive on Obama's campaign efforts by 53-40 percent, with the numbers on Romney exactly reversed: Forty percent of college graduates rate his work running his campaign positively; 53 percent, negatively

METHODOLOGY - This ABC News/Washington Post poll was conducted by landline and cellphone July 11-15, 2012, among a random national sample of 1,015 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.