WASHINGTON • If President Barack Obama wins re-election in November, Friday's jobs report may be remembered as the turning point when he shifted from slight underdog to favorite.

"Where are the jobs?" has been the question at the heart of the Republican case against Obama. Mitt Romney's campaign turns on the claim that his experience in the private sector taught him how to create new jobs. Obama, by contrast, has "failed" in that endeavor, he repeatedly says.

January's growth — a net of 243,000 new jobs created, the most in nine months and almost double what most economists had forecast — undermines that argument, both Democratic and Republican strategists agreed. The problem may not be fatal for the GOP, but if the growth continues through the spring and summer, "There's no way in the world that you can deny it helps Obama's case," said Whit Ayres, a Republican pollster.

The election-deciding question now is likely to be whether the economy does, in fact, sustain its current growth rate.

Having been burned before, the president tried to walk a careful line this time around.

"These numbers will go up and down in the coming months, and there's still far too many Americans who need a job, or need a job that pays better than the one they have now," he said during a speech in Virginia a few hours after the economic numbers were released. "But the economy is growing stronger. The recovery is speeding up."

Republicans pointed to a report earlier this week from the Congressional Budget Office that forecast a slowing economy and rising unemployment this year. And they previewed the counterargument on which they'll rely if the jobs news continues to be good: "This president has not helped the process. He's hurt it," Romney told reporters in Sparks, Nev., after the jobs numbers were released. "We can do better."

As Democrats were quick to point out, however, Republicans who insisted Obama take the blame for a poor economy may have a hard time persuading the public to deny him credit for an improving one.

They have little choice, however.