John McCain is promising to balance the ballooning federal budget by 2013 as he further promotes his jobs and economic plan in the face of a struggling U.S. economy.

That effort to zero out excess spending -- which Barack Obama's campaign says is unrealistic -- is outlined in a campaign document circulated Monday, although McCain did not mention it in a town hall meeting he held in Denver where he delivered a speech on the economy.

The 15-page policy paper says McCain will bring spending in check by chopping out wasteful spending -- a hallmark of his political identity -- and targeting what is known as "the third rail" of politics: Social Security and other entitlement programs that are about half of government spending.

"In the long term, the only way to keep the budget balanced is successful reform of the large spending pressures in Social Security, Medicare and Medicaid," reads the policy paper.

The campaign also suggests it could start dropping war costs, and start paying for debts that have accumulated since 2001.

"The McCain administration would reserve all savings from victory in the Iraq and Afghanistan operations in the fight against Islamic extremists for reducing the deficit. Since all their costs were financed with deficit spending, all their savings must go to deficit reduction," reads the McCain paper.

Click here to read the full document.

McCain and Obama continued Monday to discuss economic policy this week, promoting rival plans on housing, jobs, taxes and energy as U.S. home foreclosures continue to rise and fuel costs hover at record highs.

In his speech, McCain blasted both Congress and the Bush administration for its excess spending, but did not mention the balanced budget proposal.

"This Congress and this Administration have failed to meet their responsibilities to manage the government. government, government Government has grown by sixty percent in the last eight years -- sixty percent. That is simply inexcusable," McCain said.

"When I'm president, I will order a stem to stern review of government, modernize how it does business and save billions of dollars. I will veto every single bill with wasteful pork-barrel spending spending. You can count on it. I'll make 'em famous, and you will know their names."

Earlier this year, McCain had backed off a balanced-budget pledge -- pushing it back to the end of a would-be second term.

Obama, speaking to reporters in St. Louis after his plane made an unscheduled landing following a mechanical issue, said McCain's numbers on annual spending come up for the amount of corporate tax breaks McCain would provide. He also dismissed suggestions that he would raise taxes on the middle class.

"That is absolutely not the case, and everybody who has looked at it has said that in fact my tax cuts are three times more likely to go to the middle class than John McCain's," Obama said, adding: "Some of those statistsics that have been thrown out today by John McCain today and in the past just don't add up."

For his own budget plan, Obama said he would not promise to reduce it by 2013, although he said his program proposals are paid for.

"The first thing we're going to have to do is stop digging the hole," Obama said.

"Once we have stabilized the budget, then over time we would be able to reduce the deficit from where it is currently and where it will be. I do not make a promise that we can redue it by 2013 because I think it is important for us to make some critical investments in America's families."

Obama, who also spoke by phone to the group he was supposed to visit in person in Charlotte, N.C., said McCain offers "exactly what George Bush has done for the last eight years."

"The progress we made during the 1990s was quickly reversed by an administration with a single philosophy that is as old as it is misguided: reward not work, not success, but pure wealth," Obama said.

And earlier Monday, Politico.com reported that Obama economic adviser Jason Furman called McCain's plan "preposterous."

Citing Congressional Budget Office figures, Furman told the Web site that with an estimated annual deficit of $443 billion by 2013, a number that incorporates extending tax cuts pushed by President Bush, McCain would have to cut discretionary spending, including defense funding, by about one-third.

"McCain would have to pay for all of his new tax cuts and other proposals and then, on top of that, cut an additional $443 billion from the budget -- which is 81 percent of Medicare spending or 78 percent of all discretionary spending outside defense," the Politico quoted Furman saying.

The Obama campaign also pushed back against another criticism on the tax issue, distributing an analysis from Factcheck.org of Republican claims that Obama "voted 94 times for higher taxes." The Web site says the claim is misleading, and Obama has "voted consistently to restore higher tax rates on upper-income taxpayers, but not on middle- or low-income workers."

In an effort to blunt criticism from his Democratic opponent, McCain rolled out a statement signed by 300 economists.

"It is a comprehensive, pro-growth, reform agenda," the statement from the economists reads. "The reform focuses on the real economic problems Americans face today and will face in the future. And it builds on the core economic principles that have made America great."

In addition to McCain's pledge on earmarks, the economists touted McCain's support on several issues: a line-item veto, pausing non-military discretionary spending for one year, cutting the corporate tax rate to 25 percent, eliminating the alternative-minimum tax, simplifying the tax system, and broadening international trade.

The economists also lauded McCain's call to double the tax credit for dependent children from $3,500 to $7,000.

McCain also acknowledge the steep drop in U.S. jobs, and restated his support of free trade. While noting it "is not a positive for everyone," he promised to retrain workers who lose their jobs to overseas plants, and repeated his call to build at least 45 new nuclear plants, which he says "will create over 700,000 good jobs to construct and operate them."

The political environment is tough for Republicans, with Bush's approval rating at low levels as the U.S. teeters economically and fights terrorists in Afghanistan and Iraq. National polls vary widely, but they have one common point: Nearly all show Obama ahead of McCain.

Click here to read the analysis of Obama tax policy on Factcheck.org.

Click here to read the report in the Politico.

The Associated Press contributed to this report.