Americans believe that President Obama is doing a good job in only one area of his presidency, today’s Washington Post poll tells us.

Which one would you guess it is?

]The economy: 43 percent approve, 54 percent disapprove. Health care: 45-50. His duties as commander in chief of the military: 55-44 The federal budget deficit: 40- 56 Regulation of the financial industry: 44-50

Bear in mind, this is a poll of adults. A poll of likely voters would likely show more strongly negative results for Obama.

Our editorial of today argues that because of his light-on-specifics campaign, Obama came to power without a strong mandate. The Post poll, whose sample is, again, Obama-friendly, confirms this once again. Despite his still decent overall job approval numbers (50-47 percent), American adults disapprove of his performance in nearly every issue area surveyed. Six in ten now “lack faith” in Obama, as the Post puts in on its front page.

Meanwhile, however, the Post poll shows poor numbers for Republicans in Congress. That’s not too big a surprise — approval numbers for President Bush and congressional Democrats showed a similar pattern in 2006 — but it should serve as a lesson for the GOP. If they simply run as the un-Obama, they might win, but then they too risk coming to power without a mandate.