Jim Webb announces 2016 presidential bid

Webb adds a decidedly more conservative option for Democratic voters in a field in which former Secretary of State Hillary Rodham Clinton has tacked to the left under criticism from liberal former Maryland Gov. Martin O'Malley and socialist Sen. Bernie Sanders (Ind., Vt.).

Yet Webb is hard to pin down politically. A former Republican who served as secretary of the Navy for Ronald Reagan, Webb talks often of his military service in Vietnam. He is known for an idiosyncratic collection of positions that include opposition to the war in Iraq and advocacy for sentencing reform. An economic populist, he has accused Clinton of coming late to the conversation about excessive CEO pay, and he has regularly championed the plight of rural and working-class Americans.

One of his central challenges will be to parlay those credentials into support among an increasingly liberal Democratic primary electorate.

Also uncertain is whether Webb can appeal to women, a crucial constituency that may be difficult to win over given his past opposition to letting women serve in combat.

As an often prickly iconoclast who chafes at the demands of the campaign trail - and who has openly doubted whether he could raise the necessary money to run for president - Webb also must demonstrate that he can build a viable presidential campaign operation.

In an announcement message that ran over 2,000 words on his campaign website (which crashed for more than an hour after its release Thursday), Webb presented his differences with the rest of the field as his signature strength.

"I understand the odds, particularly in today's political climate where fair debate is so often drowned out by huge sums of money," he said. "Let's clean out the manure-filled stables of a political system that has become characterized by greed."

In the announcement, Webb mixed his policy goals with his personal narrative - and dwelled far more than his rivals on national security.