The following strikes me as a fairly clear instance of a false dichotomy:

For those who see no moral principle underlying American foreign
policy, the Holocaust Declaration is no business of ours. But for those
who believe that America stands for something in the world — that the
nation that has liberated more peoples than any other has even the most
minimal moral vocation — there can be no more pressing cause than
preventing the nuclear annihilation of an allied democracy, the last
refuge and hope of an ancient people openly threatened with the final
Final Solution.

So, to recap: you either (1) have no moral principles; or (2) agree with Charles’ Krauthammer’s "Holocaust Declaration": here’s the Holocaust Declaration:

"It shall be the policy of this nation to regard any nuclear attack
upon Israel by Iran, or originating in Iran, as an attack by Iran on
the United States, requiring a full retaliatory response upon Iran."

There are many reasons to regard such a policy is foolish and immoral.  That simple fact alone means Krauthammer cannot claim that even the most "minimal moral vocation" means we must adopt it.  Even granting (which we shouldn’t, by the way) that some form of deterrence (of Iran’s as of yet non-existent nuclear capability) is the only available option, there many different ways to achieve that goal than by apocalyptic threats.  Adopting those approaches does not mean that one abandons the (dubious to some) claim that America stands for something in the world.