Four dollar gas prices surely took a toll on the president's numbers as well, despite his repeated boasts that domestic oil production is up.
Americans know the president cannot set the price at the pump. But they are also apparently aware that his administration shut down oil production in the Gulf of Mexico and has been slow-walking drilling permits, that it banned offshore drilling over other coasts and that it denied a permit for the Keystone XL pipeline.
The Keystone denial remains astonishing for reasons that, I suspect, any Democratic pollster would tell you if you could promise absolute confidentiality.
A February Pew poll showed a 42 to 15 percent margin for building the pipeline. The fact that Obama was lobbying Senate Democrats last week to block the pipeline and that all but three voted to do so won't help the president or his party.
Last year, I described the Keystone decision as a "no-brainer." It never occurred to me that Obama would decide to favor the rich environmentalists he encounters at fundraisers over the mass of the American people who want the Canadian oil and the construction jobs the pipeline would supply.
Obama's February uptick and March downtick in the polls will probably not be the last fluctuation we will see in his political standing.
Opinion about Mitt Romney, who at this writing seems virtually certain to be the Republican nominee, could fluctuate even more. Events could shift opinion, too.
But some fundamentals are unlikely to change. Voters' focus is on economic issues and on these most oppose the president's policies. His media cheerleaders who thought his February numbers meant the election was over were fooling themselves.