The endorsement over the weekend of Obama by longtime Republican Colin Powell, the former secretary of state under President George W. Bush, gives the Democrat an opening to go on the offensive on foreign affairs.

The topic is generally considered his weakest against McCain, but Powell's backing undercut McCain's perceived dominance.

So, while in the Virginia capital of Richmond on Wednesday, Obama and running mate Joe Biden planned to meet with a group of national security advisers to the campaign.

Obama planned to talk publicly after the discussion about his approach to world affairs, and how it differs from McCain's.

The meeting comes a day after McCain questioned Obama's readiness to respond to a major crisis that the Democrats' own running mate, Joe Biden predicted he was bound to face early in his presidency.

McCain recalled his own experience as a Navy pilot preparing to launch a bombing run during the October 1962 Cuban Missile Crisis, which Biden said tested a new President John F. Kennedy. Biden said it was the kind of "generated crisis" the 47-year-old Obama would face within six months of taking office.

"America will not have a president who needs to be tested," McCain said. "I've been tested, my friends."

McCain spoke Tuesday in Harrisburg, Pennsylvania, a Democratic-leaning state that he hopes to win to offset gains Obama has been making on Republican territory.

Polls show Obama's lead widening nationwide. The latest NBC News/Wall Street Journal poll showed Obama opening up his biggest advantage over McCain with voters expressing growing confidence in the Democrat's ability to serve as commander in chief. Obama led McCain by 52 to 42 percent in the nationwide poll of registered voters conducted Oct. 17 to 20, with a sampling error of 3 percentage points.

Obama had a six-point lead in the same poll two weeks ago.

More importantly, state polls show Obama with a solid in lead in the state-by-state electoral college tallies that will ultimately determine the winner of the Nov. 4 election. Polls show Obama with a good chance of becoming the first Democratic candidate since 1964 to carry Virginia.

Obama's surge in the polls has coincided with Americans' growing anxiety over the economic crisis which has emerged as the predominant issue with less than two weeks to Election Day.

Obama's other events Wednesday in Virginia, rallies in Richmond and Leesburg, were to focus heavily on the financial meltdown. The economy is also likely to be a key theme at a rally Thursday in Indiana, yet another state that voted for President George W. Bush in 2004.

Obama arrived in Virginia on Tuesday night after spending two full days campaigning in Florida, which Bush won in both 2000 and 2004.

There, he criticized McCain for offering little more than "willful ignorance, wishful thinking, outdated ideology" to an economy in crisis.

With the chairman of the Federal Reserve and even Bush now indicating support for more economic stimulus spending by Washington, momentum is building for Congress to pass a second package after the election, an idea Obama has encouraged. But McCain has remained cool, saying only that he wants to keep his options open.

At a boisterous Miami rally with his wife, Michelle, Obama seized on that, as well as a report that a top McCain economic adviser said the Arizona senator prefers to first evaluate the impact of the $700 billion financial rescue plan passed earlier this month.

"I've got news for Sen. McCain: Hardworking families who've been hard hit by this economic crisis -- folks who can't pay their mortgages or their medical bills or send their kids to college -- they can't afford to wait and see.

They can't afford to go to the back of the line behind CEOs and Wall Street banks," Obama told a crowd of more than 30,000 that filled a waterside park Tuesday evening.

Obama is hoping to build on a slight lead in the critical battleground state of Florida before leaving the campaign trail later this week to fly to Hawaii to be at the beside of his seriously ill grandmother.

McCain was returning Wednesday to New Hampshire, a state whose primary the Arizona senator won earlier this year to revive his presidential hopes. But there were signs it was tilting toward Obama in the general elections.

Recent polls have shown Obama with a lead no smaller than 7 percentage points, prompting speculation that McCain may have to pull out and focus elsewhere if he hopes to cobble together the 270 electoral votes needed to become president.

After stopping in New Hampshire, McCain was headed to Ohio for two rallies with running mate Alaska Gov. Sarah Palin.

Campaigning in Nevada on Tuesday, Palin also referred to Biden's comments and said that Obama's own foreign policy proposals would spark the crises that would test him as president.

Playing off the Republican ticket's previous criticisms of the Democratic presidential nominee, she criticized Obama for -- among other things -- advocating sitting down with "the world's worst dictators" without preconditions and opposing the troop surge in Iraq.

Palin also repeated familiar campaign slogans, contrasting Obama as a tax-and-spend liberal with McCain as a fiscal conservative who will do more to help struggling families and small businesses. Palin said a McCain administration would create more jobs and lead the United States to energy independence.

Questioning the extent of Obama's experience has been a tactic of the 72-year-old McCain. He also questions whether the Illinois Democrat has the character to stand up to his own party and to stick with his core philosophical views.

In an interview with CNN, Palin apologized for telling a campaign audience in North Carolina last week that she loves visiting "pro-America" parts of the country and implying that some areas of the country are more patriotic than others.

Palin said she did not want her comment to be interpreted that way. "If that's the way it has come across, I apologize," she said.

The Illinois senator's decision to pull away from the campaign Thursday and Friday to be with his gravely ill, 85-year-old grandmother, Madelyn Dunham, will cut seriously into the time he has left to persuade voters to support his candidacy.

But the show of devotion to a central figure in his life could force McCain and Palin to suspend their attacks on Obama's character.

Dunham helped raise Obama, a role he highlightеd in accepting the Democratic presidential nomination nearly two months ago.