Dear Tea Party voter: You've been had.

When the good people of South Dakota voted last month to send Republican Kristi Noem to Congress, they probably believed that she would give no quarter to the lobbyists and special interest groups who enjoyed, as she put it, "throwing money at the feet of a member of Congress."

But since she defeated Democratic Rep. Stephanie Herseth Sandlin (in part by making an issue of Herseth Sandlin's marriage to a lobbyist), Noem has hired as her new chief of staff . . . a lobbyist! And on Tuesday afternoon, she was the guest of honor at a "Meet & Greet" with Washington high-rollers at the powerhouse lobbying firm Barbour Griffiths Rogers (BGR). Once these boys start throwing money at Noem's feet, she'll soon be chin deep in lobbyist greenbacks.

It was probably inevitable that the Tea Party activists would be betrayed, but the speed with which congressional Republicans have reverted to business-as-usual has been impressive.

House Republican leaders rejected a Tea Party-backed candidate as the new chairman of the House Appropriations Committee, instead installing Hal Rogers of Kentucky, who is known as the "Prince of Pork" and who once said pork is a "bad word for making good things happen."

Many Tea Party favorites, meanwhile, have discovered the appeal of Washington lobbyists' cash and advice. South Dakota's Noem is one of at least 13 incoming Republican lawmakers who have hired lobbyists to run their offices. As The Post's Dan Eggen reported last week, dozens of freshman lawmakers have already had fundraisers to collect millions of dollars from lobbyists and other deep-pocketed interests. In the month since Election Day, new Republican members had more than a dozen such "debt retirement" events.

And the parties continue. Rep.-elect Steven Palazzo (R-Miss.), for example, told supporters on his campaign Web site: "I intend to take our voice and shout it loudly to the Washington, D.C., bureaucrats and politicians to make sure they know that we want legislation reflective of true conservatism. I will make you proud."

And how, exactly, is he making his constituents proud so far? On Tuesday night, he was scheduled to be the beneficiary of a dinner fundraiser at the Republican National Committee's Capitol Hill Club. Checks - $500 for individuals and $1,000 for political action committees - are to be made payable to Steven Palazzo for Congress - and mailed to an address not in Mississippi but in Alexandria, Va.

Of more consequence is the Republicans' tax compromise, which, as the Tea Party Patriots group pointed out, violates no fewer than five provisions of the Republicans' campaign "Pledge to America." Among the broken promises in the pledge, which was designed to show that Republicans were faithful to Tea Party principles, are vows to "act immediately to reduce spending" (page 21) and to "advance legislative issues one at a time" (page 33).

Citing these violations, the Tea Party Patriots said the tax compromise makes the pledge "a joke," and the group launched a petition drive to fight passage of the measure. Jenny Beth Martin, a national coordinator of the group, said "it is an insult to those who voted them into power to procrastinate on their pledge to honor conservative principles."

So what did Republican lawmakers think of this Tea Party protest? Well, on Monday evening, the Senate held the crucial cloture vote on the compromise. The vote, which essentially guaranteed passage, was 83 to 15, and only five Republicans voted no.

Tea Party pull is stronger in the House, but even there, the powerful interests remain unchecked. Rep. Spencer Bachus (R-Ala.), the incoming chairman of the House Financial Services Committee, said last week that "Washington and the regulators are there to serve the banks." And those naive Tea Partyers thought Washington was supposed to serve the taxpayers!

But is there nobody who will keep faith with the Tea Party voter? Even Rep. Michele Bachmann (R-Minn.), a darling of the movement, is going wobbly. First, she dropped her bid for a leadership position in the House when it became clear she wouldn't win. Then she raised questions about the House GOP's plan to ban "earmark" spending on pet projects. The woman who once maintained that "all this pork is bad" told Politico recently that there must be a way to funnel infrastructure money to her district. "This isn't trying to be too cute by half of what is an earmark and what isn't," she said, "but we have to address the issue of how are we going to fund transportation projects across the country?"

Simple, congresswoman: The way you did before. In Washington, it's business as usual.