Eight years later, the sky is still empty. The place where the Twin Towers stood until this day in 2001 is no longer just a hole in the ground, but there remains a gaping hole in the Manhattan skyline, and a hole in the psyche of the metropolitan area.

Meanwhile, in some hole in a mountain on the other side of the world, Osama bin Laden remains alive and free. And if he no longer commands a worldwide network of terrorists, his very survival mocks the United States' role as the global superpower.

In the immediate aftermath of the 9/11 attacks on New York and Washington -- attacks that would have been even more devastating if not for the heroism of passengers who caused Flight 93 to crash in a Pennsylvania field -- President George W. Bush vowed to go after "the people who knocked these buildings down." And he did, for a time.

Bin Laden and his al Qaeda terrorist organization were quickly identified as the culprits behind the attacks, and the U.S. invasion of Afghanistan was aimed at ending the Taliban rule that gave them sanctuary. "I want justice," Bush declared. "And there's an old poster out West, I recall, that says, 'Wanted: Dead or Alive.' "

Before 2001 was out, U.S. forces in Afganistan had pursued bin Laden to a mountain called Tora Bora, where they believed he was hiding in caves. But the Bush administration decided to rely on local militias rather than our own troops to block the border passes into Pakistan -- presumably to avoid offending that so-called ally. The result: bin Laden got away.

By then the Bush crowd had lost interest in Afghanistan and bin Laden, distracted by the idea that 9/11 gave them the pretext they needed to oust Saddam Hussein from Iraq. Instead of pursuing bin Laden, they pursued a fantasy that toppling Saddam would cause pro-Western capitalist democracies to sprout from the desert across the Middle East. We've seen how well that worked.

Now there's a new administration in Washington, new commanders in Afghanistan and even a new regime in Pakistan. Yet bin Laden continues to elude capture. He's believed to be in one of the tribal regions of Pakistan near the Afghan border. And we're still relying on Pakistani spies and Pakistani troops with questionable loyalties to lead the hunt.

Meanwhile, our goal in Iraq has become to withdraw as quietly as possible before the Shi'a and Sunnis resume trying to annihilate one another. In Afghanistan, we're in serious danger of seeing all our gains against the Taliban reversed while we try to prop up a government that probably just commited election fraud.

Americans are reduced to wondering why our young men and women are still risking their lives in either country. How did a "war on terror" aimed at eliminating al Qaeda transform into efforts to police two patchwork nations of rival tribes and militias?

A reminder of the danger of losing focus on our real enemies came this week when a British court convicted three men of planning a coordinated series of attacks on trans-Atlantic airliners that could have killed thousands of travelers. Authorities say it was an al Qaeda plot -- directed from Pakistan -- and was days away from being carried out when it was broken up in 2006.

After the initial shock of the 9/11 attacks, Americans pulled together in determination and confidence that we would put things right: that the demons who visited that devastation on us would be punished, that the United States would reassert its dominance in the world, that we would rebuild our buildings and our national spirit. But as the years pass the evidence suggests we're just not capable of doing so -- that we've somehow lost the ability, or the will, to get things done.

The mightiest nation the world has ever known can't catch its Public Enemy No. 1. Meanwhile, we watch another of our cities laid waste by a hurricane and fumble and bungle the response. We watch speculators and financial charlatans wreck our economy and can't agree on how to fix it. We know our addiction to oil will doom us, but we can't kick our habits. We know our health care system is seriously ill but we can't agree on a cure.

And we argue and bicker and, in eight years, barely get started rebuilding the World Trade Center site. The planned memorial and museum may not be completed in time for the 10th anniversary. The first office tower might be finished in 2013, or might not. There may be no point anyhow, because the battered economy has left Lower Manhattan with a glut of vacant office space.

America's famous can-do spirit seemed to revive, briefly, with last year's election of a president who promised "Yes, we can." Mere months later his presidency is bogged down in a Washington morass of nay-saying and gamesmanship. For all his cool reasoning and polished rhetoric, he seems unable to overcome the political system's resistance to change.

So, can we? Yes, but the real question is: Will we?

On this grim anniversary, it would be worthwhile to reflect on whether we have learned anything in these past eight years about the need, in a dangerous and uncertain world, to pull together as a country, to unite as Americans -- and to get things done.