President Obama and the first lady will greet soldiers at Fort Stewart in Hinesville, Ga., on Friday at a time when his reelection campaign is focused more intently than ever on a novel and potentially fruitful voter set: military families.

On Thursday, Vice President Biden delivered a speech in which he made clear that the president’s record winding down the wars in Iraq and Afghanistan — contrasted with Republican Mitt Romney’s position of wanting to stay longer in both countries — would be a central argument of the reelection campaign.

The message from Obama and Biden is clear: They will campaign on the president’s foreign policy record and actions to bolster services for veterans while aggressively criticizing Romney on the same subjects — and issuing pointed examples of the Republican’s lack of proposals to assist returning veterans and their families.

“Governor Romney is counting on our collective amnesia,” Biden said in a campaign speech in New York on Thursday billed as the first of many that will highlight what advisers deem the shortcomings of Romney’s foreign policy proposals. “But Americans know that we cannot afford to go back to the future.”

The overall strategy gives Obama a chance to widen his audience on military matters at a time when war-weariness has grown — even among Republicans and in less Obama-friendly Southern states. The push also echoes a hallmark quality of the president’s 2008 campaign: its ability to identify supporters from unlikely regions and constituencies.

According to a Washington Post-ABC News poll conducted this month, majorities across all demographic and political groups said the war in Afghanistan was “not worth fighting.” This includes 52 percent of Republicans, 56 percent of conservatives and 50 percent of conservative Republicans.

All of those results are new high points in opposition to the war. People living in the Northeast are the most likely to say the war was not worth fighting, at 75 percent, followed by 66 percent in the Midwest and South and 59 percent in the West.

Obama’s effort to win a bigger share of the veterans’ vote than he did in 2008 could make a difference in swing states with large military populations, such as Virginia and North Carolina. Although the president lost the overall veterans’ vote four years ago, he won veterans younger than 65. And this year, he will not be running against a decorated war hero, as he did in 2008 against Sen. John McCain (Ariz.).

Foreign policy has remained largely on the margins of campaigning so far. But Biden pushed the administration’s unfolding argument into view Thursday with a sharp assault on Romney’s qualifications to be commander in chief.

Biden’s principal message is that that Romney, a former Massachusetts governor and business executive, has failed to adapt his foreign-policy views to a time when social media, international terrorism, trade and demographic change are remaking the world.

The vice president described Romney’s policies as “dangerously divorced from today’s realities,” accused Romney of being “mired in a Cold War mind-set” and said his foreign -policy positions on Russia, Iraq, missile defense and nuclear arms are “clearly and consistently stuck in the past.”

In addition to the Obamas’ visit to Fort Stewart to greet troops, veterans and military families, the president will sign an executive order establishing new protections against predatory educational institutions trying to take advantage of those who qualify for the G.I. Bill and other programs. Michelle Obama also will travel to New Mexico on Tuesday to meet with service members and families.

Both trips have been billed as official events unrelated to the campaign. But the reelection team in Chicago made clear Thursday that it plans to tout Obama’s policy accomplishments and his efforts to improve and promote services for veterans and their families.

“The president and the campaign believe that this is one of the most important issues out there as we bring more than 2 million men and women home from serving in Iraq and Afghanistan and deal with the issues they face as returning veterans,” said Rob Diamond, who served in Iraq and is the Obama campaign’s vote director for veterans and military families. “We are out there talking about that, engaging veterans, educating them, making sure they understand how much has been done.”

Obama’s celebration of the drawdowns in Iraq and Afghanistan opens him to criticism from his opponent, who has accused the president of weakening the country’s position in the world and compromising national security by pulling out too soon. Romney’s campaign made clear Thursday that it does not intend to cede foreign policy as an issue, despite poll numbers showing that much of the country agrees with Obama’s approach.

Romney has criticized Obama for not securing an agreement to leave U.S. troops in Iraq to effectively confront Iran over its nuclear program and to better manage relationships with traditional allies such as Israel.

Obama has also been accused, primarily by Republicans, of responding too slowly to the pro-democracy movements challenging long-standing autocracies in the Middle East and North Africa and failing to act decisively enough to end Syrian President Bashar al-Assad’s brutal crackdown on dissent.

“If anything, it is President Obama’s track record that has sent a message to our friends and allies, be they in governments or be they in dissident movements who want to stand with us, who want to lock arms with us, who are looking to American leadership, who are really left exposed and isolated in a way that I have not seen in American foreign policy history for years,” Dan Senor, a Romney foreign policy adviser, said during a conference call.

Obama has held up the May 2011 killing of Osama bin Laden, the decision to intervene in Libya to overthrow Moammar Gaddafi and the official end last year of the U.S. military involvement in Iraq as evidence that he has kept his 2008 campaign promises and improved American security during his term.

Although he dispatched additional U.S. forces to Afghanistan, Obama has set the end of 2014 as the deadline for American combat troops to return home — a decision Romney has called a mistake because, he says it allows the Taliban to wait out the war. Biden argued Thursday that setting the departure date has forced the Afghan government to focus on preparing for it.

Polling manager Peyton Craighill contributed to this report.