WASHINGTON - The nation's steady-but-modest job growth presents political challenges for both of November's all-but-certain presidential rivals.

Republican Mitt Romney needs an ailing economy to fully exploit his image as a "Mr. Fix-It" who can restore the nation's financial health, as he turned around the troubled 2002 Winter Olympics. President Barack Obama needs job-creation momentum to convince voters that things are moving in the right direction, even if millions of people remain unemployed.

Friday's neither-hot-nor-cold jobs report leaves both campaigns unsure of whether they can sell their narratives. Employers added 120,000 jobs last month, about half the December-February pace and well short of the 210,000 economists were expecting. Still, the unemployment rate declined from 8.3 percent in February to 8.2 percent, the lowest since about the time Obama took office.

GOP leaders were quick to note that the rate dropped largely because many Americans stopped looking for work and were not counted in the government survey.

The U.S. jobs picture was bleaker when Romney began his second presidential bid a year ago, emphasizing his experience in running the Olympic Games and reorganizing companies while at Bain Capital. He said jobs grew during his four years as Massachusetts governor, but critics note that other states had more robust growth.

GOP strategists say Romney's hopes this fall hang largely on his ability to convince voters that the current pace of recovery is unacceptable and he can substantially speed it up.

Romney, who's closing in on the Republican nomination, called Friday's jobs report "weak and very troubling."

"Millions of Americans are paying a high price for President Obama's economic policies, and more and more people are growing so discouraged that they are dropping out of the labor force altogether," he said in a statement. Obama's "excuses have run out," he said.

Obama was more upbeat at a White House gathering. "Our economy has now created more than 4 million private-sector jobs over the past two years and more than 600,000 in the past three months," he said.

"There will still be ups and downs along the way," the president said. "We've got a lot more work to do."

Democrats cling to historical data showing that presidents tend to get re-elected if the economy is improving during their fourth year in office, even if it's below normal levels. In that light, the key news for Obama in Friday's report was that jobs are still being created, not that the pace was half what it was during the previous three months.

"The trend is still his friend. But you have to worry about whether it's a fickle friend," said Jared Bernstein, a former economics aide in the Obama White House. "The question of whether the economy has truly achieved escape velocity hasn't been convincingly answered yet," he said.

Republican strategist Brian Nick said Obama will have a hard time convincing voters they should accept a poky recovery and an unemployment rate that has exceeded 8 percent for more than three years. "I think it's worse out there than maybe the administration realizes," Nick said. Many older Americans keep working when they'd rather retire, he said, and many others are so discouraged they have quit looking for jobs.

Romney's message of "we can do better" will resonate this fall, Nick said.

Strategists in both parties found modest comfort in Friday's report.

"To the extent there's a mixed message about some of the numbers, it gives Romney something to hold onto," said Joel Johnson, a Democrat who has worked in Congress and the Bill Clinton White House. Obama's allies must keep reminding voters that the 2008 economic collapse happened on President George W. Bush's watch and now "we're clawing our way out," Johnson said.

Romney must highlight the economy's ongoing weaknesses, "but you don't want to root against progress," he said.

Republicans say employment isn't the only important economic factor in the presidential race. High gasoline prices and concerns about federal spending and deficits also will work against Obama, they say.

But Republicans know they cannot count on economic trends to move their way. Romney has broadened his criticisms of Obama in recent days, saying voters should oust the president because of things he has done and unknown things he might do.

Romney repeatedly cites Obama's supposedly private comments to Russian President Dmitri Medvedev, in which Obama said he would have "more flexibility" to deal with missile defense after the election.

"He does not want to share his real plans before the election, either with the public or with the press," Romney told newspaper editors and publishers Wednesday. "By flexibility, he means that 'what the American public doesn't know won't hurt him.'"

"On what other issues will he state his true position only after the election is over?" Romney said.

Obama, meanwhile, has widened his criticisms of Romney, a tactic he may have to accelerate if employment slumps in coming months. The president said at The Associated Press annual meeting in Washington that Romney has embraced "thinly veiled social Darwinism" by backing a House GOP budget that would cut taxes for Americans, including the wealthiest, and reduce spending on many programs.

Obama's Chicago-based campaign paid less attention Friday to the jobs report than to a Washington Post story about Romney's hard-to-find financial assets and an equal-pay dispute in Wisconsin.

With no one sure what the next monthly jobs report might find, the campaigns are preparing for a tough general election in which the economy will be paramount and voters' moods unpredictable.