Congressional leaders talk in private of being boxed in by commentators such as Glenn Beck and Rush Limbaugh — figures who are wildly popular with the conservative base but wildly controversial among other parts of the electorate, and who have proven records of making life miserable for senators and House members critical of their views or influence.

Some of the leading 2012 candidates are described by operatives as grappling with the same tension. The challenge is to tap into the richest source of energy in the party — the disgust of grass-roots conservative activists with President Barack Obama and their hunger for a full-throated attack on his agenda — without coming off to the broader public as cranky and extreme…

All three figures [McCain, Graham, and David Brooks] are often irritants to establishment Republicans — but in this case, many Republicans said privately they were in agreement that they need to move beyond the hard-core right to succeed.