WHEN A ‘MODERATE’ GIVES UP ON MODERATION…. In the 109th* Congress, which ended last year, Rep. Mark Kirk (R) of Illinois was one of the House Republican caucus’ most moderate members. This year, he voted with Democrats on a cap-and-trade measure, was the lead GOP co-sponsor on an expanded hate-crimes bill, and has even supported the Employment Non-Discrimination Act.

When Kirk decided to run for the Senate, it made some sense — Illinois is one of the more reliably “blue” states in the country, but Kirk has generally preferred to keep the far-right, Sarah Palin wing of the Republican Party at arm’s length.

So much for that idea.

Illinois Rep. Mark Kirk penned a memo to Republican poobah Fred Malek hoping to secure an endorsement from former Alaska Gov. Sarah Palin for his Senate candidacy, according to a copy of the memo obtained by the Fix.

After noting that Palin will be in Chicago later this month to appear on “Oprah”, Kirk writes that “the Chicago media will focus on one key issue: Does Gov[ernor] Palin oppose Congressman Mark Kirk’s bid to take the Obama Senate seat for the Republicans?”

Kirk goes on to write that he is hoping for something “quick and decisive” from Palin about the race, perhaps to the effect of: “Voters in Illinois have a key opportunity to take Barack Obama’s Senate seat. Congressman Kirk is the lead candidate to do that.”

Keep in mind, the two Republican statewide candidates who won this week — Christie in New Jersey and McDonnell and Virginia — wanted nothing to do with Palin, while the high profile conservative candidate who embraced Palin — Doug Hoffman in NY23 — lost in a district that hadn’t elected a Democrat since the 19th century.

For that matter, as recently as last year, Mark Kirk wasn’t at all impressed with the former Alaska governor. A month before the presidential election, asked about the addition of Palin to the GOP ticket, Kirk said, “I would have picked someone different.”

Why in the world would Kirk sully his reputation like this? Because he’s facing a little-known, underfunded anti-tax activist/political neophyte in a Republican primary, and a right-wing third-party candidate is a possibility in the general election.

And with that, a once-proud moderate shifts to the right — Kirk has already denounced his own vote on energy policy — and slinks to the Palin operation, soliciting an endorsement. Mark Kirk has all the support from the Republican Party establishment he could ever want, but he’s suddenly discovered that the Tea Party crowd might be calling the shots.

As this and other GOP campaigns play out, it makes the Republican task at hand that much more difficult.

* corrected

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.