The struggle against terrorism is by no means over. More Americans will be asked to lay down their lives in this cause. And at least temporarily, threats to civilians may increase.

But the death of Osama bin Laden, and Al-Qaida's relative irrelevance to this spring's pan-Arabic uprisings, means a powerful blow has been struck in the global fight against extremism.

Next to be determined is the impact on the war in Afghanistan, as well as America's alliance with Pakistan.

Osama bin Laden signed his own death warrant when he unleashed a terrorist war against the American people. That the choice he made has at last had its way with him is a tribute to the skill, bravery and perseverance of this nation's armed forces and intelligence agencies.

President Obama struck the right note of sober satisfaction in his Sunday night address. Bin Laden's death reaffirms several salutary messages:

• To the families of 9/11 victims and all others around the world who have suffered from Al-Qaida's predations: The United States will never relent in its determination to rid the world of the terrorist threat.

• To those who may contemplate becoming enemies of America: You are choosing an unhealthy lifestyle. You may survive for a time as a cowardly fugitive, as Bin Laden did, but one day you will be found.

• To members of the military and national security forces, and their families: Your sacrifices have not been in vain, nor forgotten. The nation thanks you.

• To Muslims around the world: America has no quarrel with your faith or your societies. It is only those, like Bin Laden, who would destroy the world's peace -- your world even more than ours -- that America will spare no effort to defeat.

• To the American people: While our self-confidence and sense of common purpose have perhaps seen better days, this country retains remarkable power and conviction.

President George W. Bush committed America to tracking Bin Laden to his lair, and President Obama has made good on that vow. It is a moment for unity.

Yet while allowing ourselves these legitimate satisfactions, Americans should note that the strike on Bin Laden was not an act of vengeance but an entirely practical military mission.

The terrorist leader remained the inspirational and operational mastermind of an international conspiracy to murder innocents in this country and around the world. He was a proper military target entitled to no quarter.

With Bin Laden's recent role no doubt more inspirational than operational, it's likely that Al-Qaida and other terrorist groups will try to strike quickly to reassert their relevance. At least temporarily, dangers may increase.

But the death of the embodiment of global jihad, as well as the new wind sweeping Arab lands, leaves Al-Qaida battered.

he "Arab spring" has been a winter of discontent for those clinging to jihadists' defining grievance -- oppressive regimes propped up by U.S. support. Those regimes have toppled or are teetering due to indigenous movements that reject violence, let alone jihad.

Bin Laden's death also won't mean an immediate end to the war he triggered in Afghanistan. But it may increase the willingness of the Taliban, which harbored Al-Qaida when it ran Afghanistan, to engage in peace talks that are the only workable way to end the nearly decade-long conflict there.

That Bin Laden was hiding not in a cave, but in a compound half a mile from a Pakistani military base, raises serious questions about the Pakistani government's cooperation, or competence, or both, in the fight against extremism.

Despite shoveling over a billion a year to Pakistan for counterterrorism operations, the Obama administration did not trust the government of Pakistani President Asif Ali Zardari with its intelligence reports. Obama, and Congress, need to ask hard questions about our ostensible alliance with Pakistan.

Tackling these tough challenges, as well as continuing vigilance against terrorism and enduring the long, hard slog of Afghanistan will be better accomplished with the kind of national unity found after 9/11 and rediscovered Sunday night.

All Americans should work to ensure it doesn't dissipate again.

* * *

Note to readers: This editorial has been modified from the version that appeared only on our website in the early hours after bin Laden's death.

To offer an opinion considered for publication as a letter to the editor, please fill out this form. Follow us on Twitter @StribOpinion and Facebook at facebook.com/StribOpinion.