“Four years ago, I promised to end the war in Iraq. We did,” the president told the Democratic National Convention last month. “I promised to refocus on the terrorists who actually attacked us on 9/11. We have. . . . Al Qaida is on the path to defeat, and Osama bin Laden is dead.”

Democrats devoted a good deal of prime-time television attention to military and veterans issues in speeches during their convention. They taunted Republicans for not mentioning Afghanistan during the GOP convention, and they teased Romney for not mentioning U.S. armed forces in his acceptance speech.

Obama and congressional Democrats also have been mining the support of veterans and other voters for whom military and national security issues matter.

Last May, the president began a yearlong commemoration of the 50th anniversary of the Vietnam War by saying it was a "national shame" that those veterans came home to scorn rather than parades.

“A disgrace. It should have never happened,” he said, standing at the Vietnam Veterans Memorial on Washington’s National Mall. “That’s why here today, we resolve it will never happen again.”

Obama tapped first lady Michelle Obama and Jill Biden, the wife of Vice President Joe Biden, earlier in his presidency to lead administration efforts to support military families.

Democrats and Obama have vigorously embraced national security and military issues largely because they’ve had to, Feaver said.

“In a wartime environment, they had to compete on the national security front,” he said. “After 9/11, Democrats worked very, very hard to narrow the gap. In the last four years they narrowed that gap to the point that this summer Obama had the generic advantage over Romney.”

That wasn’t always the case. Some experts date public distrust of Democrats on national security and military issues to the Vietnam War.

Even though that war escalated under Democratic presidents – John F. Kennedy and Lyndon Johnson – the party developed a dovish reputation largely because of anti-war presidential candidates such as Sens. Eugene McCarthy of Minnesota, Robert Kennedy of New York and George McGovern of South Dakota, who appealed to younger, war-weary voters. McGovern, whom incumbent President Richard Nixon soundly defeated in 1972, died Sunday at the age of 90.

“The choice of McGovern in 1972 as the nominee signified not only did they (Democrats) regret Vietnam, they regret America’s deep involvement in the world,” said Lawrence Korb, a senior fellow at the liberal Center for American Progress who was an assistant defense secretary under President Ronald Reagan. “The McGovern narrative stuck with the Democratic Party for a while.”

The public’s faith in Democrats’ national security abilities suffered further under President Jimmy Carter when he authorized a military mission to rescue 52 American hostages held in Iran in April 1980. The mission ended miserably in the swirling sands of the Iranian desert with a heap of wrecked U.S. helicopters, the deaths of eight service members and a mortal blow to Carter’s re-election dreams.

Republicans never let Democrats forget that many of them vocally opposed sending troops to fight the first Persian Gulf War – preferring to give economic sanctions against Iraq and Saddam Hussein more time to work – even though the then-Democratic-controlled Congress authorized the deployment of troops to Iraq in 1991.

As the chair of the National Republican Senatorial Committee, then-Sen. Phil Gramm of Texas fired off a fundraising letter that branded congressional Democrats “appeasement-before-country-liberals.”

After that, Korb said, Democrats vowed never to seen as wobbly on national security again.

Bill Clinton “certainly didn’t sound like a McGovern Democrat” when he ran for president in 1992, Korb said, and he launched Republican-criticized NATO airstrikes against Yugoslavia in 1999, which halted a crackdown by Serbian forces on Albanians who were seeking independence.

Sens. Biden, D-Del., Hillary Clinton, D-N.Y., and John Kerry, D-Mass., all White House aspirants, voted to authorize the use of force against Iraq after the Sept. 11, 2001, terrorist attacks. Hillary Clinton, at times, struck a more hawkish tone on the campaign trail in 2008 than did the man who defeated her, Obama.