I got a bit sidetracked into TNR-bashing when I tried to address this subject previously, but I'm interested in Jonathan Chait's view that neoconservatism used to be an honorable, idealistic enterprise that has only very recently become a kind of mindless militarism combined with support for torture, indefinite detention, etc. Now, of course, the original neoconservative foreign policy doctrine was to oppose Jimmy Carter's injection of a larger dose of human rights into US foreign policy and to argue in favor of more vigorous American support for anti-Communist dictators. But I assume we're talking here about what might be termed "second wave" neoconservative foreign policy -- neo-neoconservatism, if you will -- and for this I think it's useful to turn to the foundational document, Kristol and Kagan's 1996 essay "Toward a Neo-Reaganite Foreign Policy".
The goal here, as explained in the essay, is a policy of "benevolent hegemony," obviously an ambiguous phrase. Their complaint with the mid-1990s status quo, however, is clearly not that the US, though hegemonic, is acting in an insufficiently beneficent manner. Rather, they believe that the US, though benevolent, isn't being as forceful as it needs to be in asserting and re-enforcing its hegemonic position. They said that "The dominant strategic and ideological position the United States now enjoys is the product of foreign policies and defense strategies that are no longer being pursued" because "Americans have come to take the fruits of their hegemonic power for granted."
I wouldn't say that the benevolence here is insincere. Rather, it's intellectually shoddy. They say that "The first objective of U.S. foreign policy should be to preserve and enhance that predominance by strengthening America's security, supporting its friends, advancing its interests, and standing up for its principles around the world." Now, Kristol and Kagan clearly believe that America's principles are good ones. Thus, standing up for our principles around the world will do good. They also believe that standing up for our principles around the world were enhance our predominant geopolitical position. We'll be doing well by doing good. "American foreign policy, should be informed with a clear moral purpose," they write, "based on the understanding that its moral goals and its fundamental national interests are almost always in harmony."
This is mighty convenient. And clearly echoed in Bush's second inaugural address where he writes that "America's vital interests and our deepest beliefs are now one." But not only are the interests of American hegemony identical to the pursuit of American values, but the pursuit of American global domination is what the rest of the world wants, too: "Most of the world's major powers welcome U.S. global involvement and prefer America's benevolent hegemony to the alternatives." And it's also good for the Republican Party, since "Over the long term, victory for American conservatives depends on recapturing the spirit of Reagan's foreign policy as well."
I don't know what you'd want to call this. It doesn't sound like idealism to me: it's confusion. Read through the essay and you'll see, repeatedly, that Kristol and Kagan have an agenda to make America more militarily dominant. They don't have any agenda for making America more benevolent except insofar as US military domination just is benevolence. The concepts of benevolence, ideals, humanitarianism, etc., don't carry any independent weight here. They believe that America should coercively dominate the world through military force. Because they believe in a dogmatic form of American exceptionalism they also sincerely believe this will be a good thing, but looked at from the outside the primary reason they believe this is that they believe American dominance is the highest good.
Neo-neoconservatism is, thus, essentially continuous with James Burnham's early Cold War calls for the creation of a US-dominated "universal empire" and with the late-19th century school of imperialism. It's not a coincidence that John McCain's political idol is Teddy Roosevelt. One is tempted at times to say that neoconservatism has improved upon the imperialism of yore by giving it a shiny idealistic gloss, but if you look it up classic imperialism turns out to have had the gloss as well.
(I should note for the record that I became convinced of the essential continuity between neo-neoconservatism and Burnham through Peter Beinart's A Fighting Faith and between neo-neoconservatism and late 19th century imperialism through John Judis' The Folly of Empire).