The Arizona senator refused to answer a reporter's question Sunday about what plans he might be considering.
Addressing several dozen volunteers at his campaign headquarters outside Washington, McCain promised some of his signature "straight talk" about the state of the race. National and many battleground state polls have shown him trailing Obama amid the deepening market crisis.
"We're a couple points down, OK, nationally, but we're right in this game," McCain said to cheers. "The economy has hurt us a little bit in the last week or two, but in the last few days we've seen it come back up because they want experience, they want knowledge and they want vision. We'll give that to America."
McCain said he and running mate Sarah Palin would continue campaigning hard in the three weeks left before Election Day, in places like Ohio, Pennsylvania, New Mexico, Nevada and Colorado.
The two planned a joint appearance Monday in Virginia, a Republican stronghold turned battleground this time.
"We're going to spend a lot of time and after I whip his you-know-what in this debate, we're going to be going out 24/7," McCain said.
The two men will debate Wednesday at Hofstra University on Long Island, N.Y. CBS News anchor Bob Schieffer will moderate the 90-minute forum.
Still, McCain promised to run a "respectful" campaign in the weeks to come.
"I respect Senator Obama, we will conduct a respectful race and be sure everyone else does too. But there are stark difference between us," McCain said.
Meanwhile, Sen. Lindsey Graham, R-S.C., said McCain was considering policy proposals that would cut taxes on investments.
"I think it goes along the lines of now's the time to lower tax rates for investors, capital gains tax, dividend tax rates, to make sure that we can get the economy jump-started," Graham said on CBS' "Face the Nation." "It will be a very comprehensive approach to jump-start the economy by allowing capital to be formed easier in America by lowering taxes."
McCain already has laid out proposals to address the crisis, including a $300 billion plan for the federal government to buy distressed mortgages and renegotiate them at a reduced price.
The Arizona senator has said his plan is necessary to get thousands of bad mortgages off the books in order to stabilize home values and open up credit. But critics said the plan would do little more than reward financial institutions that made the bad loans to in the first place.
On Friday, McCain called for legislation that suspends for one year the requirement that investors age 70½ begin to liquidate their retirement accounts. The Arizona senator said it would be unfair to force seniors to sell their stocks when stock prices have tumbled so severely. Obama aides said the Illinois senator favors a similar effort.
Obama also has offered plans to address the fiscal crisis but nothing as sweeping or controversial as McCain's mortgage proposal.
On Friday, the Illinois senator announced a $900 million plan to temporarily extend an expiring tax break that lets small businesses write off investments up to $250,000 immediately, rather than over the course of several years.
Aides said Obama also wants to extend the Small Business Administration's disaster loan program to help small businesses that cannot access other sources of capital, as well as eliminate fees on SBA loan guarantees and increase the size of loans that could be covered. They put the cost at $5 billion.
Both candidates voted for the $700 billion bailout proposal Congress passed and President Bush signed into law earlier this month.
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