In an election as close as this one, it is the little intangibles—that intuitive sense of confidence (or lack thereof) about a candidate that ambivalent voters carry with them into the booth—that can make all the difference. And although we’ve heard that this election will be almost entirely about the U.S. economy and not foreign policy, President Obama will make his national-security record a centerpiece of his closing night at the Democratic National Convention this week.

Why? Because arguably no Democrat since John F. Kennedy has run as tougher and more trustworthy than the Republicans on national security. Obama plans to do just that. He has chosen Sen. John Kerry—a war hero and candidate to succeed Hillary Rodham Clinton as secretary of State in a second term—to deliver a speech arguing that Obama “has restored America’s leadership in the world” and “has taken the fight to our enemies,” according to a campaign official who spoke on condition of anonymity.

The Obama campaign will contrast the president’s record with Romney’s hawkish but scattershot statements on the stump, characterizing the GOP’s usual we’re-tougher-on-defense tack as empty and dangerous rhetoric. Romney “has embraced the go-it-alone, reckless policies of the past,” the official said, adding that Democrats will seek to identify Romney with the overextensions of the Bush administration.