IRAN TO IRAQ: An excellent piece by Kenneth Pollack in the latest Foreign Affairs on why we should overthrow Saddam ASAP, and why it will require a U.S. invasion.
The best argument against doing so is, as set out by people such as Steve Chapman, is that:
a) Saddam has been deterred up to this point from using unconventional weapons by our (and Israel's, in the context of the Gulf War) broad hints at nuclear retaliation if he were to use such weapons, and
b) that deterrence would likely not work if Saddam knew we were coming to finish him off; he'd have no incentive not to fire everything he has (i.e., tons of chemical weapons, whatever rudiments of a nuclear weapon he has, etc.)
The problem with this argument is that it underestimates the likelihood (which, absent an act of God, is close to a certainty given Saddam's track record) that we will have to run the risk of nuclear confrontation with Saddam anyway, and it will be on his timetable if the U.S. does not act. Think a re-run of the 1990 invasion of Kuwait, only this time with a promise by Saddam that he will use nuclear weapons against us if we try to replay the Gulf War.
As people should have learned from the 1990s, sanctions do not work for the same reasons that cartels do not work; it depends on cooperation of many actors, every one of which has a tremendous incentive to cheat. Only "regime change" will be able to prevent Iraq from acquiring nuclear weapons, and, as seen by the rationalizations of those such as Leon Fuerth and Jacob Weisberg, there will be no shortage of statesman-sounding reasons not to attack Saddam until we are forced with the risk of letting Saddam run free in the world or facing nuclear attack.