Washington ? On jobs and taxes, the top Republican presidential rivals are locked in a fierce game of one-upmanship. They’re all trying to outdo each other in offering the boldest economic plan for the campaign to unseat President Barack Obama next November.

Despite some notable differences in the blueprints, they all are built around the central theme that Obama’s stimulus programs haven’t worked and his job creation record is dismal. Example No. 1: Unemployment is holding at a painfully high 9.1 percent.

“We knew ultimately that the 2012 election was going to be a big referendum on the president,” said Douglas Holtz-Eakin, former director of the Congressional Budget Office who was the chief economic adviser to Arizona Sen. John McCain’s 2008 presidential campaign. “But Republicans also have to say what they would do. It’s not enough to say we don’t like what’s going on.”

Texas Gov. Rick Perry teased rival Herman Cain — “I’ll bump plans with you, brother” — when both rolled out ambitious proposals for a single-rate flat tax. That’s a concept hailed by numerous Republicans and some Democrats for its simplicity, yet it never has managed to attract much congressional support. Former Massachusetts Gov. Mitt Romney is the lone major GOP contender not calling for a flat or flatter tax.

The 2012 contenders also are serving up a platter of familiar conservative fare: calls for deep spending cuts, reduced government regulation and an emphasis on private enterprise as the true engine of job growth and prosperity.

The plans underscore the party’s attempt to respond to the biggest voter concerns of the day and capitalize on what they see it as Obama’s chief vulnerability, the still shaky recovery. The candidates claim their various plans would help create millions of private sector jobs; just how is not always clear.

With polls showing that most people support increasing taxes on the wealthiest households, as Obama and Democrats are proposing, the GOP flat-tax plans would largely end up as a boon to the wealthiest, independent analyses suggest.

The tax debate coincides with spreading protests, inspired by the Occupy Wall Street movement, against economic inequality. The nonpartisan Congressional Budget Office recently reported the top 1 percent of American earners doubled their share of national income over the past 30 years, to 20 percent.

Some of the GOP plans show depth, complexity and sophistication, Holtz-Eakin said. Not every economist is as charitable or sees the GOP offerings as workable.

“I don’t think any of the plans can be taken too seriously as actual policy,” said Bruce Bartlett, who held top economic posts in the Ronald Reagan and George H.W. Bush administrations but now considers himself a political independent.

“The Republican goal is to nominate the person who is the most committed, most articulate in terms of the Republican philosophy. What they’re competing for is who best represents that core philosophy and articulate it in a way that the base finds satisfying,” Bartlett said.

No matter that some GOP dogma, such as an insistence that cuts in business taxes and government regulation will spur private-sector job growth, “is economic nonsense,” Bartlett said.

All the GOP rivals would pare federal regulations.

Rep. Michele Bachmann, R-Minn., would kill the Environmental Protection Agency and repeal the 2010 Dodd-Frank financial industry regulation law. Romney is proposing a 10 percent cut in the federal workforce. Former Pennsylvania Sen. Rick Santorum wants to repeal all regulations put in place by Obama. “The federal government kills jobs. We don’t need more programs and bureaucrats telling business how to operate,” he says.