Which is party of 'strength'?

With a Democratic convention unconventionally dominated by military themes, Sen. John Kerry is taking an aggressive step to shrink the gap between himself and the president on national security - and reverse decades of Republican dominance on that front that has held since the days of the Vietnam War.

In part, the Massachusetts senator has no choice but to make security a cornerstone of his campaign: Polls show that Americans still see Iraq and the war on terror as the top issues concerning the nation, ahead of the economy.

But the Kerry campaign also believes it has a candidate - and a race - uniquely suited to shift the political paradigm. As a Vietnam veteran running against a president who did not go to Vietnam, Kerry is casting himself as better prepared to make decisions about matters of war, a candidate who is both "strong and wise," as Democrats repeatedly noted throughout the week.

"It's a move for the jugular, but on the other hand ... he may not have an option," says Fred Greenstein, a presidential historian at Princeton University.

To this end, Kerry has adopted more hawkish positions than many members of his own party - in some cases trying to get out in front of the president in the muscularity department: He is proposing to add 40,000 troops to the US military, and has put forward a detailed plan to secure loose nuclear material in Russia. He is calling to extend the 9/11 commission's mandate for another 18 months.

At the same time, however, Kerry has sharply criticized Bush for the manner in which he took the country to war - alienating allies and leaving the US to shoulder too much of the burden.

In many ways, Democrats are presenting a Kerry presidency as a return to a consensus-based, less ideological foreign policy: The Bush administration, they say, has pursued a reckless foreign agenda that represents a radical departure from the established framework of the past 50 years, under both Republican and Democratic administrations.

"Bush's main claim to the presidency stems from his self-appointment as the war president of this country, and therefore the question is very relevant - namely is he an appropriate war leader?" says Zbigniew Brzezinski, former national security adviser under President Carter. "One way to deal with that is to go at it head on. His foreign policy represents the repudiation of 55 years of bipartisanship in foreign policy when it comes to national security."

Republicans say that Kerry is pinning all of his national-security credentials on service in a war that happened more than three decades ago - and that his two-decade-long record on security issues in the Senate is hardly reassuring. They point out that he voted against nearly every major weapons system during the cold war, voted against the 1991 Gulf War, and, while he voted in favor of the current Iraq war, voted against the $87 billion in funding for it.

Indeed, analysts say Kerry's Senate record has been notably absent as a focus of his campaign - in part because so many of the votes he cast seem counter to the positions he is now adopting.

"I can't think of too many candidates in recent history who have spent so much time trying to walk away from their own voting record," says William Mayer, a political scientist at Northeastern University.

Earlier this week, Republicans released a video documenting Kerry's alleged "flip flops" on Iraq over the course of this presidential campaign.

"They would obviously like us to believe that Senator Kerry has a principled position on national security, but his own words completely refute the notion that he is a strong and decisive leader," said Republican National Committee Chairman Ed Gillespie at a press conference.

Polls suggest Kerry has already passed a "threshold" test on national security - with a majority of voters saying they would trust him to be commander in chief.

But he still trails Bush on measurements such as which candidate would do a better job handling the war on terror, and who has a clearer plan for Iraq.

The importance of that factor is enormous: Although Kerry leads Bush on most domestic issues - from healthcare to the economy - Bush's strength on the war on terror is still propping up his numbers overall, essentially keeping the race tied. If Kerry can eliminate the president's lead on the war on terror, he would almost certainly open up a large lead overall.

While incumbent presidents tend to have an advantage among voters in terms of being seen as a strong commander in chief, Democrats believe Bush has actually made himself vulnerable on this front, with polls showing a majority of voters do not think the war in Iraq was worth the cost. They also argue that Americans have largely made up their minds about Bush's foreign policy - and that their opinions are not likely to change between now and November - creating an opening for Kerry, if he can convince them he would do better.

"Iraq and foreign policy are key things to understanding why Americans are turning away from [Bush]," says Democratic pollster Stan Greenberg.

Democrats have crafted a muscular message for their campaign. The word "strength" shows up 106 times in the text of the platform entitled "Strong at Home: Respected in the World." Speakers have followed suit.

Key speakers' quotes of strength at 2004 Democratic National Convention:

"Strength and wisdom are not opposing values." - Former President Bill Clinton

"We lack neither strength nor wisdom." - Former President Jimmy Carter

"I firmly believe America needs new leadership that will make us stronger at home and respected in the world." - Former Vice President Al Gore

"We must be strong, we must be innovative, and we must be bold." - Gov. Tom Vilsack, Iowa

AP