When Los Angeles teacher Marcy Winograd saw her Democratic representative in Congress making excuses for George W. Bush’s warrantless wiretapping program on NBC’s Meet the Press in February, she decided that someone had to challenge Jane Harman’s acquiescence in Bush’s reckless agenda. So Winograd, a veteran activist who had been instrumental in getting the California Democratic Party to take a firm stand against the war in Iraq, leapt into the June 6 primary. She quickly found that others shared her frustration with Harman; Winograd’s been endorsed by Progressive Democrats of America, Southern California Americans for Democratic Action, the Western Region of the United Auto Workers union and a half-dozen presidents of local Democratic clubs. Recently her supporters blocked an early Harman endorsement by the state party after Winograd told a caucus: “When elected, I will have the courage to cut funding for the war in Iraq, to say no when the imperial George Bush wants to wiretap your home without a warrant and to immediately sign on to legislation for universal single-payer national healthcare.”

Winograd is one of a growing number of challengers to Democratic House and Senate incumbents accused of being too supportive of the war in particular, and of the Bush Administration in general. Not since the early 1970s, when anti-Vietnam War insurgents like Ron Dellums in California, Father Robert Drinan in Massachusetts and Elizabeth Holtzman in New York defeated entrenched Democrats in primaries, has there been such ferment over foreign policy within the ranks of the party.

Ironically, a Democrat who helped form the antiwar caucus that in 1970 wrested the US Senate nomination in Connecticut away from a conservative incumbent, Thomas Dodd, was a young lawyer named Joe Lieberman. This year Lieberman, seeking re-election to Dodd’s old seat, faces a serious primary challenge from telecommunications executive Ned Lamont, who entered the race after Lieberman emerged as the highest-profile Democratic defender of Bush’s “stay the course” line on Iraq. Arguing that Connecticut needs “a Democratic senator,” Lamont has attracted more than 7,000 campaign donations (many collected through the Internet, where liberal bloggers are promoting his candidacy) and hundreds of volunteers for a drive to collect 15,000 signatures to secure him a place on the August 8 primary ballot.

The backing that Lieberman enjoys from party leaders, particularly the state’s popular senior senator, Chris Dodd, still makes him a favorite for the nomination. But Lamont, with personal wealth to draw on and support from several Connecticut chapters of Democracy for America (DFA), the grassroots organization that grew out of Democratic National Committee chair Howard Dean’s 2004 presidential campaign–and a personal endorsement from Dean’s younger brother Jim, a Connecticut resident and the national chair of DFA–has shaken Lieberman. After he was booed at a March Democratic Party dinner, the senator, whose approval rating among Connecticut Democrats has dropped seventeen points in the past year, announced he had “not foreclosed the option” of quitting the party that nominated him for Vice President in 2000 to seek re-election as an independent.

Lieberman isn’t the only Democratic senator facing an antiwar primary challenge. In New York, former National Writers Union president Jonathan Tasini is stepping up his long-shot bid to displace likely 2008 presidential contender Hillary Clinton; elsewhere, antiwar candidates have announced or are weighing primary bids against Democratic senators, including Washington’s Maria Cantwell and Wisconsin’s Herb Kohl. Challengers are also taking on the candidates of DC Democrats for open House and Senate slots. Ignoring calls for party loyalty, three county Democratic parties in Pennsylvania have refused to back the Democratic Senate Campaign Committee’s favored candidate, Bob Casey Jr., over progressive Chuck Pennacchio. In Maryland, former NAACP president Kweisi Mfume, who’s made his antiwar stance central to his primary bid for an open Senate seat, is in a dead heat with Representative Ben Cardin, a favorite of party insiders.

The fights reflect a tension between party leaders, who say the best way to capitalize on Bush’s declining approval is by uniting behind incumbents and centrist candidates, and activists, who argue that the party needs to nominate antiwar candidates who can articulate the frustration of voters. Even some liberals, like Barbara Boxer, are counseling progressives against backing primary challenges to tepid incumbents. “If we are going to seize this moment, not squander it,” says Boxer, “we must focus on the vast number of differences we have with our Republican opponents, not the few we have with each other.” In the Harman-Winograd race, Harman is circulating “despite our differences on the current war” endorsement letters from Boxer and Representative Barbara Lee; Winograd reminds grassroots Democrats that, unlike Harman, she’ll vote with Boxer and Lee to bring the troops home.

Frustration with the war is such that Harman is now emphasizing her support for an (admittedly vague) “exit strategy”–confirming the view that, win or lose, this year’s primary challenges are forcing Democratic incumbents to be more critical of Bush. But that’s not good enough for Winograd. She describes her contest with Harman as “an iconic struggle that asks, Who does the Democratic Party represent–grassroots Democrats or the Bush Administration?”