(CNN) -- Alaska Gov. Sarah Palin suggested Tuesday that it would be Sen. Barack Obama's policies that would spark the international crisis that Sen. Joe Biden has said would be likely within months of Obama taking office.
At a fundraiser Sunday night, Biden, the Democratic vice presidential nominee, said that after taking office, "It will not be six months before the world tests Barack Obama like they did John Kennedy. ... We're going to have an international crisis, a generated crisis, to test the mettle of this guy."
He added that the Obama administration would need people to stand with it at the time because "it's not going to be apparent initially ... that we're right."
"I guess we have to say, "Thanks for the warning, Joe,' " Palin, the Republican vice presidential nominee, told supporters during a rally in Reno, Nevada.
She speculated that instead of the crisis being generated by another world leader, as Biden suggested, an international crisis could be sparked by Obama's willingness "to sit down with the world's worst dictators without preconditions," to send troops into Pakistan to try to kill Osama bin Laden and other top al Qaeda officials, or to draw down U.S. troops in Iraq.
In response to earlier criticism of the comments from Sen. John McCain, the GOP presidential candidate, Obama-Biden campaign spokesman David Wade issued a statement saying:
"Sen. Biden was making it clear that history has shown presidents face challenges starting on day one, and with our nation fighting two wars and 21st century threats abroad, we know that we need steady leadership in tumultuous times, not the erratic lurching and stubborn ideology of John McCain."
But Palin zinged her Democratic counterpart, saying, "I guess the looming crisis that worries the Obama campaign right now is Joe Biden's next speaking engagement." Watch how the 'Palin effect' could save McCain »
Trailing in polls nationally as well as in battleground states, the Republican ticket in recent days has been aggressively jumping on any opening given to it by the Democratic presidential ticket.
To reach voters in critical swing states, Palin and McCain have also increased the number of interviews they have done with local media outlets, in part to blunt the Obama campaign's huge cash advantage.
On Sunday, the Obama campaign announced it raised a record $150 million in contributions in September.
McCain on Tuesday continued to hammer Obama for the comment the Democrat made to "Joe the plumber" in which -- as he defended his decision to raise taxes on couples earning more than $250,000 a year while cutting taxes for people with lower incomes -- Obama said that "when you spread the wealth around, it's good for everybody." Truth Squad: Is Obama attacking 'Joe the plumber'? »
"After months of campaign trail eloquence, we've finally learned what Sen. Obama's economic goal is. ... Sen. Obama is more interested in controlling who gets your piece of the pie than he is in growing the pie," McCain told supporters during a rally in Bensalem, Pennsylvania. Watch McCain jump on Joe Biden's comments »
McCain also accused Obama of waffling on which team he was backing in the World Series between the Philadelphia Phillies and the Tampa Bay Rays, which begins Wednesday.
"It's kind of like the way he campaigns on tax cuts, but then votes for tax increases after he's elected. Or the way he says he backs the middle class and then goes and attacks Joe the plumber after he's asked a tough question," McCain said.
Obama, however, has said he was rooting for the Phillies and has never said he was also rooting for the Rays.
When he was joined by a number of Rays at a rally in Florida on Monday, Obama said, "I am a unity candidate bringing people together, so when you see a [Chicago] White Sox fan showing love to the Rays, and the Rays showing some love back, you know we're onto something right here."
On Tuesday, Obama kept his focus on Florida and the economy, the issue that is foremost on voters' minds. Polls also suggest that voters have more trust in Obama's handling of the current financial crisis than in McCain's.
During an economic roundtable discussion in Lake Worth, Florida, Obama called the crisis "the worst since the Great Depression" and blasted the Bush administration for not doing enough to help "Main Street."
"While President Bush and Sen. McCain were ready to move heaven and earth to address the crisis on Wall Street, President Bush has failed to address the crisis on Main Street -- and Sen. McCain has failed to fully acknowledge it," Obama said. "Instead of commonsense solutions, month after month, they've offered little more than willful ignorance, wishful thinking and outdated ideology."
The nation's economic woes appear to be affecting the presidential race more than at any previous time this election cycle, according to a poll released Tuesday. Watch how Americans feel anxious, angry »
More than three-quarters of voters who responded to a new survey by CNN and the Opinion Research Corp. say the United States is in a recession, and 40 percent say another depression is likely to hit the country within a year.
According to the new poll, 61 percent of registered voters say the economy is extremely important to their vote, a jump of three points since June and more than 10 points higher than the next most important issue on voters' minds: terrorism.
CNN's Dana Bash, Paul Steinhauser and Scott J. Anderson contributed to this report.