Meet the "aggressive progressive," the "progressive warrior," the "proven, principled progressive" and the Democrat who tells voters simply, "call me a liberal if you’d like."

Welcome to the Democratic primary in Northern Virginia's 8th Congressional District, which is open for the first time in more than two decades. The retirement of Rep. James P. Moran (D) spurred 10 (!) Democrats to run in one of the most liberal districts in the country. So why are the candidates branding themselves with catchy tag lines? Because they need to find a way to stand out in a field that lacks big, sweeping policy differences.

The early frontrunner in the race seems to be former lieutenant governor Don Beyer. Beyer calls himself the "proven, principled progressive," with an emphasis on "proven." A former ambassador to Switzerland and Lichtenstein who bundled contributions for President Obama, Beyer outraised the field and recently hit the airwaves with six-figure TV ad buy right now, while most others are not on TV.

State Sen. Adam Ebbin is underscoring his record of legislative accomplishments. As others were trotting out their catchphrases in the first candidate forum this month, Ebbin encouraged voters to just "call me a liberal of you’d like."

During the 120-minute gathering, the Democratic hopefuls took part in a lightning round. Moments of discord were few and far between.

Take gay marriage, for example. Asked whether they support it, the candidates' answers ranged from "yes" to "yes indeed" to "10,000 percent."

What about employers denying their workers access to certain health services on religious grounds? Good idea?

"Absolutely not," said talk-radio host Mark Levine, who bills himself as the "aggressive progressive."

Democratic congressional candidate for Virginia's 8th district answers questions about his his nickname, his former boss Barney Frank, and if gay marriage will get federal support by 2016. (Theresa Poulson/The Washington Post)

"Pardon my French, but hell no," chimed in Alexandria Mayor Bill Euille, who was seated next to Bruce Shuttleworth, the "progressive warrior."

So, you get the idea.

The candidates met again last week, where once again they mostly agreed on big issues. In their closing remarks, they used anecdotes from the campaign trail and their lives to distinguish themselves from the competition.

"People are hurting out there. And I am running to be your voice," said Del. Patrick Hope.

Former Northern Virginia Urban League president Lavern Chatman said, "We have a unique opportunity to have more diverse representation in this district." Chatman is an African American woman.

Moran's district includes Arlington County, Alexandria, Falls Church and part of of Fairfax County. Obama won more than two out of three votes there in 2012. In short, Republican nominee Micah Edmond seems destined to be an afterthought in November.

"This is the 8th congressional district," said Mount Vernon District Democratic Committee member Laura Sonnenmark, who has not decided which candidate to support. "It's okay to have someone give us some red meat."