Perhaps the most useful thing Nate Silver has ever done was compiling this chart:

Although not a perfect measure, Silver’s chart does a fairly good job of identifying which Republicans are significantly more conservative or liberal than their electorates. This, of course, is important in identifying where primary challenges can be most effective since it indicates where Republicans can reasonably expect to win general elections with challengers who are significantly more conservative than the incumbents. Last election cycle, conservatives took aim at Murkowski and Bennett, two of the worst outliers on the chart. Voinovich has retired. The next two natural targets on the chart are pretty obvious, and both are feeling the heat.

Hatch, for his part, has been busily trying to convince everyone that the TEA Partiers have got him all wrong, he’s one of them and always has been. Lugar, on the other hand, bolstered by the success of Dan Coats in last year’s Indiana primary, seems to be taking the opposite approach. A couple weeks ago, I got an email from the Lugar campaign which argued, apparently with a straight face, that Lugar deserved to go back to the Senate because he was almost as good as Mitch McConnell. Plus, it included this photograph of Lugar, originally captioned “CONSERVATIVE” which my colleague Moe Lane helpfully re-captioned for accuracy:

Yesterday’s WSJ notes that Lugar has begun meeting with IN GOP activists, and things aren’t going so well. In fact, the best thing that can be said for Lugar’s chances right now is that there are too many people lined up to primary him. Everywhere Lugar goes these days he encounters skepticism and outright hostility from his constituents:

When Mr. Lugar came to this farming town of 500 people Saturday to build bridges with a local tea-party group, he found mostly skepticism.

“You seem to feel you’re somehow indispensable in Washington,” Bob Callahan, 65, a retired salesman from Monticello, told the senator at meeting in an elementary-school gym. He compared Mr. Lugar to the professional football quarterback Brett Favre, saying: “There’s nothing sadder than an athlete that doesn’t know when to get out.”

Eighty miles south in Indianapolis about 40 people huddled Friday with FreedomWorks, a group based in Washington, D.C., that helps coordinate tea-party groups across the U.S. On the agenda, in a closed-door meeting in a hotel ballroom, was how to unify behind a Republican to challenge Mr. Lugar in next year’s primary. “Our knuckles are going to get bloody,” said Monica Boyer, 35, a secretary and mother of four with Hoosiers for Conservative Senate.

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Republican challengers to Mr. Lugar include Indiana state Treasurer Richard Mourdock. Another favorite of conservatives, state Sen. Mike Delph, may also run.

Sal Russo, the GOP strategist behind the Tea Party Express, which put millions of dollars behind candidates in Republican primaries last year, said in an interview he would spend money in Indiana in 2012.

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The 70 or so in attendance mostly grilled Mr. Lugar on other matters: his views on concealed handguns (he opposes them) and the United Nations (he wants the U.S. to remain a member).

In an interview, Mr. Lugar said there were “really vivid contrasts” between his views and those of some in the audience. “I will try to do my best,” he said of his efforts to win over tea-party faithful. “In some cases I may not be successful, but that’s debate.”

I guess it is to his credit that Lugar is not trying to run away from his record, which would be impossible given its volume. If Indiana conservatives can unify behind a single candidate, the GOP could finally have a Senator from Indiana who is worthy of the Indiana electorate.