must give alternative?

It is a unique and, to me, rather uncharming feature of Realist thinking that its adherents can often legitimately collapse to the following argument:

Even if the war was publicly misjustified, and even if it has been executed incompetently, and even if we have alienated all of our allies and turned the world against us, and even if there's a chance that it will make everything worse, and even if the Bush administration would never listen to you anyway, you can't legitimately criticize the war, or decisions within the war, without explaining what we should now do to get out of a mess that you didn't create.
I disagree. Criticizing the process of a decision is absolutely legitimate. It is legitimate politically because it helps condition future political decisions, shapes debate, and inspires activism. It is ethically legitimate unless you believe, and believe strongly, that the ends always justify the means.

Demanding an alternative assumes a unitary purpose to political discussion and debate. The drive for such a unitary purpose makes possible all sorts of minor rhetorical tyranies, from the forced marginalization of process-based criticism, to the entrenchment of the kind of normativity Pierre Schlag, Richard Delgado and others indict in legal thinking (and actually a particularly bad kind of normativity even worse than legal, because it affects people across a wider spectrum and works its way into other categories of thinking). In my opinion, the most dangerous thing about this so-called normative thought is that it crowds out the space to assess, to describe, to investigate, the structures and contexts, the assumptions and symbolic patterns, that sustain the conditions that caused the problems.

Demanding an alternative also assumes a political and social universalism that simply doesn't exist. This is particularly frustrating to me because many times my criticism of political decisionmaking stems precisely from the way in which people are cut off from that decisionmaking--an exclusion primarily based on people's lack of resources and lack of powerful credentials. This results in a nonsensical argument: I say "the Bush Administration screwed up and didn't listen to anyone" and your answer is "Well, what would you have them do now?" If it weren't so sad, it would make a good joke.

Moreover, demanding an alternative seems to encode a kind of temporal particularism, a "temporal stasis" to borrow a term from Dungeons and Dragons. It assumes not only the universal social class described above, but a unitary moment from which to act. It says the choice of a political subject is always in the here and now, that urgency must always trump wisdom.

In short, the demand for an immediate alternative that could only be enacted by the very agents whom we've spent a great deal of time criticizing is a demand that comes from those who don't share our concerns. It's a demand from a different world, a world which, to steal from Ursula LeGuin, we have sort of "walked away from"--not to escape our responsibility to the suffering people in that world, but to reject the notion that we have to work exclusively within its conceptual and political rules.