Three big speeches to go in DNC-land: Biden, Bubba, and, of course, Barack. Tonight, featuring the former two, will focus on national security. Congressional Quarterly fills in the details:

Democrats will use Wednesday night to try once again to persuade voters they can protect the nation's national security interests -- a political hurdle that has tripped up their party for decades.

After seven years of war in Afghanistan and five in Iraq, an army of Democratic policy experts, activists, veterans and students have developed a plan to use the party convention to turn the national security debate to their advantage. Their plan is to reframe the issue, presenting a new strategy that looks beyond the Iraq war in pursuit of both U.S. and international objectives.

Obama's campaign, while not coordinating directly with these groups, has a parallel plan to showcase his support among key security-minded constituencies, including Iraq veterans, military families, and retired flag officers who oppose Bush administration policies.

Tomorrow night, meanwhile, will reportedly focus on the economy. But expect some flourishes to be thrown in:

Thursday is the 45th anniversary of Martin Luther King's I Have A Dream speech and Obama, the nation's first black major-party nominee, says he will note how far the nation has come. But nuts and bolts are his top priority.

"I'm not aiming for a lot of high rhetoric," Obama said. "I'm much more concerned with communicating how I intend to help middle-class families live their lives. I want people to come away saying, 'Whether I'm voting for the guy or against the guy, I know what he stands for. I know what he believes.' "

Helping families "live their lives," however, is certainly no modest goal--and, as USA Today notes, Obama's expansiveness can lead to critiques:

Obama's lofty language has been an irresistible target for his rivals, from Democrat Hillary Rodham Clinton's charge during the primaries that he's "just words" to McCain's attempts to cast his opponent's oratory as a sign that Obama is a vacuous celebrity and/or an arrogant messiah wannabe.

Some advance buzz on Obama's speech--including the press rumors that it will be held in front of a quasi-"Greek temple"--shows that this line of attack is unlikely to fade soon.

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