On the Republican side, the debate will be between neocons who believe - like Weekly Standard editor William Kristol - that while the idea of waging war to reform Iraq was correct, the implementation was flawed; and the realists who fault the idea itself. Those include people like former National Security Adviser Brent Scowcroft.
In the meantime, many analysts say talk of a neocon twilight is premature.
That's "not simply because ... they have the ear of some very well-placed people in the White House," says Mr. Toensing, "but because their ideas resonate with the American public."
The neocons post-9/11, he continues, have been especially successful at highlighting the link between terrorism and a lack of democracy, particularly in Arab and Islamic countries. The next leap - from an action being merely "good" to seeming an imperative for US security - makes sense to many Americans, he adds.
Observers say it was a series of columns by classic conservative George Will that signaled the Republicans' foreign-policy war. Saying the administration's Iraq policy has been too "neo" and not sufficiently conservative, Mr. Will hammers his central point: As exceptional as America may be, it should not blindly believe it can overcome the force of culture in foreign places.
Others point to a battle of the books as a sign of a fight for foreign policy. On one side are titles like "Bush League Diplomacy: How the Neoconservatives are Putting the World at Risk," or "America Alone: The Neo-Conservatives and the Global Order"; on the other side is "An End to Evil," by neocon dean Richard Perle and former Bush speechwriter David Frum.
In the latter, the authors warn that "the will to win [the war on terror] is ebbing." But that alarm bell is simply a "note of panic" that the neocon star is fading, says Stefan Halper, a GOP foreign-policy specialist and coauthor of "America Alone."
Active in three previous Republican administrations, Mr. Halper admits that his book's objective is to move neocons "to the periphery of power, where as a special interest group they belong."