(From 11 scholars and opinion writers, answers to a hypothetical: What would the situation be now if the United States had not invaded Iraq?)

The only thing I remember from grad school is the "hypothetical counterfactual" - an idea that attempts to answer the intellectually elusive question: What if?

For example, what if the Founding Fathers had promoted German as America's language instead of English? Would we have sided with the Central Powers instead of the Allied Powers in World War I?

An interesting question, but, obviously, no one knows. But a round of mental gymnastics such as this can teach us important lessons about how and why we made the decisions we did - with an eye to making sound judgments in the future.

So what if the United States hadn't invaded Iraq in March 2003? It's my view that, absent an Iraqi invasion: Terrorism, beyond Iraq, would be rampant, including another attack in the United States, and Middle Eastern freedom and democracy, excluding Israel, would be nothing more than a concept.

There are more terrorist attacks in Iraq than anywhere else, and if al-Qaeda's Abu Musab al-Zarqawi and his terrorist cohorts weren't wantonly killing "infidels" in Iraq, they'd be wantonly killing innocents somewhere else - guaranteed.

Osama bin Laden and Zarqawi had no intention of moving off into retirement after 9/11. In fact, the Iraq invasion, in addition to deposing the very dangerous Saddam Hussein, may well have the added benefit - if al-Qaeda is defeated there - of serving as Islamic terrorism's "last stand."

Moreover, without the invasion, we wouldn't be seeing any hint of democratic progress in the Middle East. Since the spring of 2003, there has been some form of "democratic" elections in Iraq, Afghanistan, Lebanon, Egypt, Saudi Arabia, and the Palestinian territories.

This month Afghanistan will go to national polls for the second time in two years, and next month Iraq will conduct a national referendum to ratify its constitution. Even the Palestinian Hamas and Lebanese Hezbollah terrorist groups participated in elections this year.

And without the military success of the Iraq invasion, would Libya have given up terrorism and its WMD programs? Without the presence of U.S. forces in neighboring Iraq, would Syria have withdrawn its 15,000 troops from Lebanon after 30 years? Not likely.

We'll never know the hypothetical counterfactual of invading Iraq. But we can be certain that there hasn't been a terrorist attack on the homeland in four years and that the seeds of freedom and democracy appear to be taking root in Middle East.

Peter Brookes is a Senior Fellow for National Security Affairs and Director of the Asian Studies Centre at The Heritage Foundation, and was former Deputy Assistant Secretary of Defense for Asian and Pacific Affairs in the Office of US Defense Secretary Donald Rumsfeld from 2001-2002.