Caroline Glick: The fateful hour has arrived.

After the September 11 attacks, George W. Bush was revered by Americans and lovers of liberty around the world. His soaring rhetoric and stated determination to fight for all that is good and sacred in this world won the hearts of millions and instilled in them the hope that the great battle for civilization had been joined by a force capable of defending it.

America is the greatest nation on Earth and it does have the ability to defend the world against regimes like Iran and its allies. It can prevent Iran from acquiring nuclear weapons. It can take those weapons out of North Korea’s hands. It can bring Damascus to its knees and force it to cough up Iraq’s arsenal of pathogens. And no, military might is not the only way for it to accomplish these tasks.

But America cannot, and it will not accomplish any of these goals if it continues to abide by strategies and frameworks that serve only to strengthen its enemies and permit its “allies” to behave perfidiously. It cannot and will not defend the world from evil, demonic regimes like Iran’s if it continues to allow the likes of the EU, Russia, Egypt and China to undercut its will at every turn.

This week Teheran threw down the gauntlet. The greatest battle of this war - the battle to prevent the world’s most dangerous regime from attaining the most dangerous weapons known to man - has begun. The moment has arrived for President George W. Bush to make clear if he is, in the final analysis, the leader of the free world or its undertaker.