As Manhattan’s skyline fell down, Americans stood up. We took to our feet and raised the flag, pledging solidarity to our nation, our values – and most importantly, our fellow Americans. We were outraged, bereaved, shaken – unified. On that day, we confirmed what we had long suspected: being an American is more than a title; it is a duty. And the images of first responders rushing headlong into crumbling towers affirm that courage and honor define our privilege.

We lost thousands of lives, the Twin Towers and our feeling of invincibility. The attacks on our soil awakened within us a resolution that we must defend not only our lives, but also our way of life. For the first time, we saw our new enemy up close – we experienced firsthand the ruthless aggression of Islamic extremists.

The events of that day didn’t begin, but certainly brought to the forefront, our war against Islamic extremists – an enemy that despises the very idea of America. The freedoms we enjoy, the values we hold dear, the equality we fight to achieve make us the target of extremists. But as this war wages on today, there is solace in knowing that conflict in defense of liberty is a fight forever justified.

History shows us that every American generation is tasked with defending the idea of America. Make no mistake about it – this is our generational challenge. It was my grandparents' generation that fought the Nazis. It was my parents' generation that fought the Communists. Our generation is fighting the Islamic extremists – and like the generations that preceded us, we will be victorious.

Five years ago today – out of devastation grew patriotism, pride and strength. These events – now woven into the fabric of American and human history – will be remembered not for the destruction that transpired, but the compassion that followed. And the world will know for generations to come that as Manhattan’s skyline fell down, Americans stood up.