In today's war the force we're fighting is Islamic fascism, the desire to place the whole world under sharia law. Some remnants of the old fascist movements such as the Ba'ath party are allied with it against us. This is not a war that can be avoided. America is truly the Great Satan to the Islamofascists--nothing is more dangerous to them than the seductions we offer. Every teenager who sees America and wants to live a life different from his or her parents' is a threat to that way of life. If their children can make their own choices the mullahs preaching hate and stasis will find their mosques empty as the new generations vote with their feet. So the only way to preserve their way of life is to destroy America, or at least drive it far enough away to reduce the temptations.
Driving America away looked doable in the '80s and '90s. One car bomb in Lebanon killed twice as many American troops than we've lost in Operation Iraqi Freedom, and the Marines left. Other attacks have gone unanswered or had symbolic retaliation only, while America fled Somalia, tolerated Iraqi defiance of the cease-fire terms, and encouraged Israel to make concession after concession to the people who want to destroy it.
So Al Qaeda has gone for bigger targets, promising its recruits victory over the infidels. And three thousand people died on 9/11.
Now America can't ignore the world. We'd much rather stay home and watch stories about politicians and interns, but that means accepting more blows from an enemy that wants to kill us all and is collecting the weapons to do it. So we have to take the offensive, destroy this threat, and then we can return to our blissful isolation.
Simply killing the current members of Al Qaeda will no more end this war than sinking the six carriers that attacked Pearl Harbor would have ended World War II. We have to drain the swamp that breeds the terrorists. Dictatorial countries with stagnant economies leave young men with no path to pursue any peaceful ambition, leaving them the perfect recruits for the Islamofascists. Countries with a democratic government or a growing economy produce few terrorists, and none as dangerous as Al Qaeda or Hezbollah.
Afghanistan was the first target by necessity, but it was a shelter for Al Qaeda, not its breeding ground. The Taliban was propped up by Saudi money and Arab fighters. Now Afghanistan is back in its natural state--feudalism, with warlords giving nominal allegiance to Kabul. The people have better lives now, but with 20% literacy (many of those only reading the Koran) full democracy will take many years.
Literacy was invented in Iraq--it's much better ground for the first Arab democracy. With Saddam out of the way, we can midwife a new society where people can choose their own path, and have many options open to the. Terrorism will be much less appealing to them as they leave the Islamofascists behind and move into the 21st century. Politics seems to be coming naturally to the Iraqis. Already they're marching in the streets making demands, with no fear of being executed for expressing their views. I have great hopes for them and intend to support their struggle where I can.
When the people of the other Arab nations see Iraq flourish in freedom and prosperity they will know that they don't have to keep living their miserable lives and obeying their hated dictators. Then freedom will spread across the region the way it did in Europe in 1989. On that day America can see the Arab world as friends, not threats, and we will be free to bring our troops home and live without fear.
In the meantime we have to prevent the existing Islamofascists from killing us. Removing Saddam has helped in our shorter-term goals. Terrorist groups sheltering under his rule have been captured or destroyed. Suicide bombers no longer win $25,000 for their families. Those terrorists wanting to kill thousands can no longer hope to obtain new WMDs from Iraq. Other rogue states are becoming more cautious--both Iran and North Korea have been moderating their stands lately. (Syria, alas, seems to be making "bet you can't do it again" its diplomatic policy. Hopefully they'll back down before America has to prove it can do it again.)
On the individual level every Al Qaeda recruit can see that attacking America is a quicker route to ignominious death than to glory. Osama bin Laden expressed this as "When people see a strong horse and a weak horse, by nature, they will like the strong horse." America has made it clear that it's the strong horse. That alone makes us more secure from attacks, as fewer men become terrorists.
The war is far from over. We have at least as much work before us as the Allies did between Sicily and Berlin, spread over many more years. But we can be confident that we will win this war, and the world will be a better place when we're done.