It appeared on April Fool's Day -- but it was no joke.

I'm referring to an opinion piece in The Washington Post, penned by two feisty Vermonters who want the Green Mountain State to secede from the United States. Their case is an eclectic mix of progressive and libertarian concerns. "Over the past 50 years," they argue, "the U.S. government has ... abandoned the democratic vision of its founders and eroded America's fundamental freedoms." They yearn for a return to a government where "every citizen is a legislator who helps fashion the rules that govern the locality."

"Some of us," they conclude, "seek permission to leave."

Reading this prompted the jaded Washington insider in me to speculate about how the defection of Vermont's congressional delegation would affect Congress, and why. While the loss of Vermont's lone at-large representative in the House would go largely unnoticed, the departure of Vermont's two senators would immediately shift control to the Republicans. The most intriguing aspect of this involves freshman Sen. Bernie Sanders -- the first avowed socialist ever to serve in the U.S. Senate -- and the crucial role he plays as part of the historically unprecedented coalition that now controls the Senate: 49 Democrats, one socialist, and Independent/Democrat Joe Lieberman of Connecticut.

But, one might respond, isn't Sanders, a socialist who espouses some very radical things, so far outside the ideological mainstream that it's unfair to focus on him? After all, as a House member Sanders favored massive government redistribution schemes and sky-high taxes on the "rich"; the creation of a government-run health system; slashing military spending in half; turning our energy policy over to the government; repealing the Patriot Act; and terminating all trade agreements ("workers in both the United States and in foreign nations," he once said, "would be better off without free trade agreements").

Yet a review of all 125 votes cast by Sanders since his election reveals that, far from being an outlier, Sanders walks almost side by side with his colleagues in the Democratic Party. Thirty-two Democratic senators voted with him at least 95% of the time. Another 13 saw things his way between 90% and 95% of the time. None voted with him less than 85% of the time. On the 15 cloture votes held thus far in 2007 (votes to end debate on contentious issues, i.e., the best test of party loyalty), Sanders has proven even more reliable than some Democrats, voting with Majority Leader Harry Reid (D.-Nev.) every single time.

Indeed, you find virtually no daylight between the voting records of the rumpled Vermont socialist (who once said, "I don't mind really if millionaires vote against me; they probably should") and millionaire Senate colleagues such as Jay Rockefeller (D.-W.Va.), Ted Kennedy (D.-Mass.), Herb Kohl (D.-Wis.), Barbara Boxer (D.-Calif.), Dianne Feinstein (D.-Calif.) and Frank Lautenberg (D.-N.J.). Each voted with Sanders at least 95% of the time. His fellow freshmen, some of whom campaigned as reasonable moderates, have also voted in lockstep with him. Finally, the senate's two top Democrats, Harry Reid and Majority Whip Dick Durbin (D.-Ill.), voted with Sanders 96% of the time.

The affinity of many elected Democrats for the worldview Sanders espouses is nothing new. In fact, during the last Congress (when Sanders served in the House), about two-thirds of House Democrats agreed with him at least nine out of 10 times. In the House, though, Sanders' lone vote didn't matter; in the Senate, Sanders has already determined the outcome six times, including whether to remove the requirement that U.S. troops be withdrawn from Iraq, grant tax relief to small businesses to offset the negative effects of increasing the minimum wage, mitigate the harmful effects of the Alternative Minimum Tax, and extend collective bargaining rights to federal airport security workers.

This remarkable convergence of Senate Democrats with the lone (admitted) socialist in Congress suggests one of two things. Take your pick. Either Senate leaders have successfully domesticated Sanders, convincing him to tow the "moderate" Democratic Party line against his better judgment. Or maybe there really is no distinction between a real socialist and a modern liberal in today's Democratic Party. 

Mike Franc, who has held a number of positions on Capitol Hill, is vice president of Government Relations at The Heritage Foundation.