It was inevitable that as the years since 9/11 passed, the grief would become less intense and the commemorations of the atrocity would become more subdued. So it is probably no surprise that today’s ceremonies on the 11th anniversary of the day Islamist terrorists killed thousands of Americans will be far less imposing than those held last year. The depth of the tragedy is such that for those who experienced it and who lost loved ones, no memorial service can ever suffice to express the sorrow and the anger this day conjures up in the souls of Americans. But just as December 7 eventually became just another day in the calendar, 9/11 will also be transformed into a date in history like Pearl Harbor; a mute reminder of the past rather than the gaping wound it once was.

Yet there is something distinctly unsatisfying, even distasteful about the way Americans are “moving on” from 9/11. The closure from Pearl Harbor was made possible by the sacrifice of millions of American serviceman who secured total victory over the Japanese and their German Nazi allies. After 1945, there could never be a sense of unfinished business about the memory of those lost on the “date that will live in infamy,” as President Franklin Roosevelt memorably expressed it. But 11 years after 9/11, Americans cannot say that. Osama bin Laden, the mastermind of the crime, is dead, as President Obama and his supporters constantly remind us and for that we are thankful. But Al Qaeda is far from destroyed. The Islamist terrorist war against the West is not over and those who act as if it is are doing the country a disservice.

Americans are, we are constantly told, weary of the wars that followed 9/11 and it is hard to blame them for that. The United States has left Iraq and the mess that our exit is causing may undo the victory that President Bush’s surge made possible. We are soon to leave Afghanistan, a decision that may eventually lead to power for Al Qaeda’s Taliban allies. Throughout the Middle East, terrorists loosely affiliated with Al Qaeda persist. So do others that call themselves by different names. In Gaza, the Islamists of Hamas have created an independent terrorist state in all but name. In Lebanon, the Islamists of Hezbollah now dominate the government. In Iran, an Islamist state funds terror throughout the region and works to build a nuclear bomb as the West pursues ineffectual measures to stop them.

It is true that more than a decade of hard work by American intelligence services has prevented another 9/11. Given that most experts thought a second tragedy was almost inevitable, this is no small achievement. But the problem with this battle is that it needs more than constant vigilance from those tasked with protecting the country. It also requires the sort of patience that the citizens of democracies rarely possess.

Americans have throughout the last century vacillated between a belief in a global mission that understood that U.S. security would only be found by bringing democracy to the world and a small-minded isolationism that asked nothing more than to be left alone. We may be on the brink of another such bout of isolationism as Americans turn away from the world and seek only to balance their own budget or to do some nation building at home, depending on which political party you are listening to. But the problem with such an impulse is that foreign perils have an annoying habit of intruding on our national solitude.

America’s encounter with Islamist terror did not begin on 9/11. Nor did it end on that date or even on the day that bin Laden was dealt justice. As long as Islamists plot against America and our allies, we will never be able to truly move on from it. That is a hard thing to accept and it is to be expected that we will do anything to avoid thinking about it. Rather than congratulating ourselves for having the maturity to move on from 9/11, it is this hard truth that we should be contemplating today.