Republican leaders rallied behind presumptive presidential nominee Mitt Romney as President Obama officially began his reelection bid.

Newt Gingrich and Rep. Michele Bachmann of Minnesota, who both dropped out of this year's Republican primary contest, said Romney would prove better at creating jobs and reducing the country's debt than Obama. Each had criticized Romney during the primary campaign for failing to be sufficiently conservative.

"Compared to Barack Obama, Mitt Romney is a solid conservative," Gingrich, the former House speaker, said on CBS's Face the Nation program. "As far as I'm concerned, I've endorsed him."

American employers in April added the fewest number of jobs in six months and wages stagnated, adding to concern that the nearly three-year-old economic expansion is cooling. The 115,000 increase in payrolls was less than forecast, Labor Department figures showed last week in Washington.

Both the Romney and Obama campaigns are preparing for a close election, with the most recent Gallup daily tracking poll, completed May 4, showing the race essentially tied.

The economy will be a "net plus" for the president once voters consider Romney's platform on taxes and regulation, Sen. Charles Schumer (D., N.Y.), said on CBS's Face the Nation.

Romney "wants to give further tax breaks to the wealthiest among us," Schumer said. "He wants to further deregulate many industries. That's what got us into this trouble to begin with."

Sen. Marco Rubio of Florida, a potential Republican vice presidential pick, called the latest jobs report "abysmal" and said Obama was trying to blame Republicans for the country's current economic condition because his own polices have failed.

"Things keep getting worse under his watch," Rubio said on Fox News Sunday. "He doesn't want to run on that record." Obama "asked us to hire him four years ago on the promise that he knew how to fix this economy," Rubio said. "That's the standard we should judge him by. The standard he set."

He said Hispanics have been disproportionately affected by the administration's "bad policies with regards to the economy."

In an interview with NBC's Meet the Press, Vice President Biden defended the administration's economic record, saying the slowing of job growth in April doesn't indicate the economy is stagnating. "There's still a lot of people in trouble," Biden said. "But there's no stagnation."

The administration's economic policies have created a "steady path" for recovery that would be quicker had Republicans not blocked some stimulus proposals, Biden said.

Support for Obama may decline in the swing state of Virginia, which the president won in 2008 with the help of turnout among African Americans and college students, former Rep. Tom Davis (R., Va.) said on CNN's State of the Union. The president also may not do as well the northern part of the state, where the voters who supported him in 2008 are among the wealthiest in the country, Davis said.

"When you start putting a bull's-eye on people making over $100,000, $250,000 a year, that's where they live and I think it's going to be some problems for the president moving down the line," Davis said, referring to the Obama administration's backing for higher taxes on the wealthiest Americans.