A legislative proposal that was once on the fast track is suddenly dead. The Senate will not consider a plan to extract billions in extra taxes from megamillionaire hedge fund managers.

The decision by Senate majority leader Harry Reid, the Nevada Democrat, surprised many Washington insiders, who saw the plan as appealing to the spirit of class warfare that infuses the Democratic party. Liberal disappointment in Mr Reid was palpable at media outlets such as USA Today, where an editorial chastised: "The Democrats, who control Congress and claim to represent the middle and lower classes, ought to be embarrassed."

Far from embarrassing, this episode may reflect a dawning Democratic awareness of whom they really represent. For the demographic reality is that, in America, the Democratic party is the new "party of the rich". More and more Democrats represent areas with a high concentration of wealthy households. Using Internal Revenue Service data, the Heritage Foundation identified two categories of taxpayers - single filers with incomes of more than $100,000 and married filers with incomes of more than $200,000 - and combined them to discern where the wealthiest Americans live and who represents them.

Democrats now control the majority of the nation's wealthiest congressional jurisdictions. More than half of the wealthiest households are concentrated in the 18 states where Democrats control both Senate seats.

This new political demography holds true in the House of Representatives, where the leadership of each party hails from different worlds. Nancy Pelosi, Democratic leader of the House of Representatives, represents one of America's wealthiest regions. Her San Francisco district has more than 43,700 high-end households. Fewer than 7,000 households in the western Ohio district of House Republican leader John Boehner enjoy this level of affluence.

The next rung of House leadership shows the same pattern. Democratic majority leader Steny Hoyer's district is home to the booming suburban communities between Washington, DC, and Annapolis. It boasts almost 19,000 wealthy households and a median income topping $62,000. Mr Hoyer's counterpart, minority whip Roy Blunt, hails from a rural Missouri district that has only 5,200 wealthy households and whose median income is only $33,000.

Income disparity - to use the class warrior's favourite term - is greatest among the districts of lawmakers that lead each party's campaign arm. Maryland senator Chris Van Hollen chairs the Democratic congressional campaign committee. With more than 36,000 prosperous households and a median income of nearly $70,000, his suburban Washington district even out-sparkles Ms Pelosi's. In contrast, fewer than 5,000 such wealthy households are found in the largely rural district of his Republican counterpart, Tom Cole from Oklahoma. The median income there is only $35,500.

Democratic politicians prosper in areas of concentrated wealth even in staunchly Republican states such as Georgia, Kansas and Utah. Liberal congressman John Lewis represents more than 27,500 high-income households in his Atlanta district. The trend achieves perfect symmetry in Iowa. There, the three wealthiest districts send Democrats to Washington; the two poorest are safe Republican seats.

Soon this new political demographic may give traditional purveyors of class warfare the yips. To comply with new budget rules, liberal Democrats on Capitol Hill are readying a tax increase of at least $1,000bn over the next decade. Ms Pelosi says she wants to extract all of this from "the wealthy". When has a party ever championed a policy that would inflict so much pain on its own constituency? At what point will affluent Democrats crack and mount a Blue State tax rebellion?

Will we see the emergence of a real-life Howard Beale, the television anchorman played by Peter Finch in the movie Network ? Beale was disgusted with America's deteriorating 1970s economy and culture. One night he snapped and implored viewers to get out of their chairs. "Go to the window, open it, and stick your head out and yell: 'I'm mad as hell and I'm not going to take this any more!' "

Or will Democratic voters follow a different cinematic lead, that of the fraternity pledge in Animal House? Perhaps they will accept these tax rises as a political and economic hazing and greet each new tax hike with: "Thank you, sir. May I have another?"

Michael Franc is vice president of government relations for The Heritage Foundation (heritage.org).