Few could have predicted the path this nation has taken since the terrorist attacks of 10 years ago today.

In the aftermath of those traumatic events the United States was a country united in purpose. While no one should have expected that political differences and bickering would not reemerge - this is after all a republic - the horrors of that day reminded Americans that the ideals they held in common were more important than their differences. It seemed then that on the big issues, at least, their leaders could work together.

Instead, 10 years later, political polarization is greater than at few other times in the nation's history. On the big issues of this time - jobs, deficit control, tax policy, balancing free markets and regulatory safeguards - there is no hint of compromise, but only a drive to gain political advantage.

One thing has worked out better than expected. The images of 9/11 seared in their minds, Americans braced for more attacks. Certainly they would come. But, remarkably, there has been no large-scale successful organized terrorism attack on U.S. soil since.

Most people expected war, in fact they demanded reprisals for the suicide attacks that killed nearly 3,000 people. In the decade since the U.S. has relentlessly pursued the al-Qaida terrorism network, killing many of its leaders, thwarting its plots, eviscerating its organization and culminating last May with the killing of its mastermind, Osama bin Laden.

The U.S. also undertook two traditional wars, one to oust the illegitimate and twisted Taliban leadership in Afghanistan that had provided al-Qaida a safe haven. Tragically, a second, unjustifiable war was launched to oust an Iraq leadership that had nothing to do with the 9/11 attacks nor posed any serious threat to America.

Ten years later U.S. troops remain in both countries and still actively fight in Afghanistan, a conflict that has spilled into Pakistan.

These interventions, which almost certainly would not have happened but for the events of 9/11, have cost 225,000 military and civilian lives and up to $4 trillion in U.S. spending. Those are the findings of a new report by scholars with the Eisenhower Research Project at Brown University's Watson Institute for International Studies.

More than 31,000 people in uniform and military contractors have died. The figure includes 6,000 U.S. soldiers. The $4 trillion estimate takes into account military expenses, veterans' care and interest payments, since the U.S. borrowed most of the money. The number is four times the projected and much debated deficit for fiscal year 2012.

On Sept. 10, 2001, the U.S. was fiscally and economically strong, the unchallenged leader of the world. A new president, George W. Bush, was trying to find his political legs after victory in a controversial election. The U.S. people enjoyed a false sense of security that its powerful military assured domestic safety from attack.

Ten years after 9/11 the nation is poorer, scarred by the loss of so many lives in combat, saddled by a politically divided Washington that cannot effectively govern, yet safer for having pursued al-Qaida and invested heavily in improved national security.

As 9/11 now begins the slow fade into history, America must move on, while not forgetting its lessons. The withdrawal from Iraq should proceed as planned. President Obama also plans gradual removal of the military forces from Afghanistan. It's time.

The nation's elected leaders must move beyond politics always focused on gaining advantage in the next election and find the ability to compromise and govern. The people should demand it.

While persistent attacks have diminished al-Qaida, it remains a threat and new terror concerns will emerge. Pakistan, an unstable country beset with assorted jihadist groups and with a large nuclear arsenal, could prove the gravest danger over the next decade. When it comes to security, the U.S. cannot let down its guard.

The U.S. shall never return to what now seems like the relative naivete of Sept. 10, 2001, nor should it, but recalling the spirit of togetherness that followed those attacks, the nation can do better.