LEAVE THE 17TH AMENDMENT ALONE…. Over the last year or so, the evidence that the Tea Partiers’ agenda can be pretty far out there has been overwhelming. What you may not have heard, however, is that this same far-right crowd is especially incensed about the existence of the 17th Amendment — the constitutional provision that empowers the electorate to choose their own senators, rather than state legislatures doing it, as the Constitution originally mandated.

David Firestone notes today that Tea Party activists and their allies are quite serious about wanting to repeal the 17th Amendment, thinking that it would weaken the federal government and the power of special interests.

Around the country, Tea Party affiliates and some candidates have been pressing for repeal — though there also has been a lot of hasty backtracking by politicians once the voters realized the implications. In Idaho, two candidates in last month’s Republican primary for the First District House seat said they favored repeal, including the winner, Raul Labrador. Steve Stivers, the Republican candidate in an Ohio Congressional race, said he wanted to repeal the amendment, until his Democratic opponent, Representative Mary Jo Kilroy, made an issue of it, after which he seemed to back off.

Utah, the only state that refused to ratify the amendment, remains a particular hotbed of prelapsarian sentiment. Tim Bridgewater, who ousted Senator Robert Bennett of Utah as the Republican candidate in that race, blasts the 17th Amendment on his Web site: “We traded senators who represent rights of states for senators who represent the rights of special interest groups.”

As nutty as this sounds, the “Repeal The 17th” initiative really is important to Tea Parties. Marc Ambinder recently noted that the position has “become a part of the Tea Party orthodoxy.”

But as with much of the “movement’s” agenda, Republican candidates are struggling with the bizarre demands. The GOP is desperate for right-wing support, and therefore willing to consider endorsing a repeal of the constitutional amendment, but notice how often candidates backtrack, fearing that voters would think the idea is a little too ridiculous to be taken seriously.

It reinforces one of the year’s most obvious conundrums for the Republican Party — endorse extreme ideas and earn Tea Party support, or appeal to the American mainstream. For Dems, it also offers an opportunity to remind voters just how nutty the GOP activist base has become: “They’re so far gone, the Republican base wants to take away your right to elect your own senators.”

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.