The mainstream press, especially conservative commentators, would have you believe the antiwar primary challenge to Sen. Lieberman is the greatest assault on democracy since women got the right to vote. In actuality, single-issue challenges have a long history in America, indeed, our current political landscape was, to a large extent, shaped by a successful challenger to an entrenched Republican incumbent in New Jersey way way back in 1978, when disco, detente, and Jimmy Carter reigned supreme.
In the late 1970s a small group of economists and commentators, backed by financial interests, made the rounds in Washington peddling something they called "supply side economics" -- cutting taxes, especially for the rich, especially capital gains -- which, they claimed, would enable the economy to grow like a crystal city in the Superman movies. They were laughed out of town. The Democrats still believed, at least somewhat, in social equality (those were the days) and Republicans still believed in actually balancing a federal budget. (It does seem hard to believe, I know).
The supply siders realized that if they were ever going to escape the political margins, they would have to speak in a language politicians understand -- votes. In early 1978 they targeted Clifford Case, a long-term Republican incumbent senator, known for being able to get along with Democrats. Their candidate was Jeff Bell, essentially a non-entity, but running on a supply side platform.
On primary day, Bell won, pulling off an upset that sent shockwaves among the Republican political establishment. Bell went on to get clobbered by Bill Bradley, trading in his N.Y. Knicks uniforn for a Senator's coat and tie, that November, but the supply siders didn't care, they were willing to sacrifice Case's career and even the hapless Bell to get their message across. By winning the primary, they had planted a flag in Republican electoral politics.
Two years later Ronald Reagan then running for the Republican nomination, signed on to the supply side program (and was attacked by George Bush Sr. for believing in "voodoo economics") and after winning election that fall, put supply side economics into practice. The result, of course, was devastating for the American political economy, causing sky high deficits that brought government activism to a standstill and helping to bring about the "Brazilization" of America with ever-widening gaps between the haves and the have-nots, but the moral is one liberals can learn from: single issue primary challenges, if successful, can indeed change the world.