Time Magazine’s latest poll shows Barack Obama’s job-approval rating sinking underwater for the first time in the series at 44/50.  Despite this, Obama still leads in head-to-head matchups against leading Republican contenders, but only barely against Mitt Romney.  Time chalks this up to a significant gender gap that still favors Obama, at least in their survey of 838 likely voters:

Obama leads Romney, the former Massachusetts governor who sits atop the GOP presidential field, 46% to 43% among likely voters. The President has opened a double-digit lead over Perry, 50% to 38%, highlighting concerns percolating through the GOP that the Texas governor would face a steep uphill climb should he capture the nomination. Obama also boasts a 49% to 37% edge over businessman Herman Cain, whose strong Tea Party support has propelled him toward the top of Republican ranks in recent weeks.

In each case, the President was buoyed by his performance among female voters. Women prefer Obama over Romney by eight percentage points (49% to 41%), by 17 points over Perry (53% to 36%) and by 21 points over Cain (53% to 32%).

Obama’s strength in head-to-head match-ups with potential Republican rivals belies his own shaky footing with a weary electorate. Just 44% of voters approve of the President’s performance, a slip of four points since a similar poll was conducted in June. Four out of five respondents say the U.S. has veered off track, and 71% think the country’s clout in the world is waning. A scant 5% report feeling positive or unconcerned about the state of the nation.

Color me at least a little skeptical of this poll.  For one thing, Time doesn’t include any data in its sample on the demographics of its likely voters, or even the larger set of general-population adults.  What are the party-affiliation percentages? Age demos?  Regional demos?

I’m also a little skeptical of a poll that finds 85% of the adults in the survey are registered to vote, and then says 83.8% of its sample are “likely voters.”  I think that Time needs to ask a few more questions than “will you vote” to determine the likelihood of casting a ballot in November 2012.  Besides, in the subset of 904 registered voters, only 90% said they will “probably” or “definitely” vote, which comes to 814 respondents, not the 838 they list as “likely.”  “Definitely” got 84%, which comes to 759 respondents.

As an entry in the Time series, though, Obama’s drop in support is notable.  As recently as June, Obama had a 48/46 approval rating, which was an improvement over the August 2010 pre-midterm poll showing 46/45 — which probably overstated his support somewhat.  Now he’s dropped further than his pre-midterm standing, and this after a monthlong attempt to recast himself as a class-warfare populist.  That effort has taken Obama in the wrong direction, which is why I’m very skeptical that a proper sample of likely voters would show him in majority territory over either Rick Perry or Herman Cain, or near it against Mitt Romney.