Resident Scholar Joshua Muravchik

Our choice is stark. Accept Iran with an atom bomb or cripple its nuclear program by force. Nothing else will stop Tehran.

States rarely get talked out of instruments of power, especially not fanatic ones. China and Russia will veto sanctions that might really bite, but those would not work anyway. Neither India nor Pakistan abandoned their bombs in response to sanctions. The ouster of Iran's hard-liners might change things, but under President Mahmoud Ahmadinejad and Supreme Leader Ali Khamanei, extremists seem more firmly entrenched than a decade ago.

The dangers an Iranian bomb would present are intolerable. Iran is the pre-eminent sponsor of terrorism. Iranian weapons are responsible for a large share of U.S. casualties in Iraq. Our forces in Afghanistan have intercepted Iranian arms shipments to the Taliban. Argentina has indicted Iranian officials for blowing up a Buenos Aires Jewish center. Palestinian President Mahmoud Abbas has said Tehran was behind Hamas' armed takeover of Gaza. Iran provides haven to fugitive leaders of al-Qaeda. The list goes on.

A nuclear attack by terrorists would be almost impossible to deter. Against whom would we threaten retaliation?

Iran also might launch a nuclear missile at Israel, which Ahmadinejad wants "wiped off the map." Israel could strike back, but so what? Akbar Hashemi Rafsanjani boasted "the use of an atomic bomb against Israel would totally destroy Israel, while (the same) against the Islamic world would only cause damage." And he's the "moderate" alternative to Ahmadinejad.

Even without initiating an attack on us or an ally, Tehran would use its nuke as an umbrella over its drive to dominate the Middle East and beyond. Like Lenin and Hitler, Admadinejad has a grand vision. "Thanks to the blood of the martyrs, a new Islamic revolution . . . will soon reach the entire world," he crows. Bolstered by nukes, Iran's aggressive ambitions would not be stopped without a big war.

Only strikes against Iran's nuclear facilities can forestall these terrible scenarios. This would not require a "declaration of war," an antiquated concept that has not been employed since World War II and rarely before. We would send no troops, conquer no land. Rather, we would act in pre-emptive self-defense.

At stake are supreme issues of national safety. The president alone, as Alexander Hamilton said, is positioned to operate with "decision, activity, secrecy, and dispatch." Of course, Congress can block presidential action, but in this case, most members will be satisfied to stand clear and let the president do what must be done.

Joshua Muravchik is a resident scholar at AEI.