No war can be won by defense alone. There is a reason White House counterterrorism chief John Brennan recently felt confident enough to declare that al-Qaida was “on the ropes.” Progress came from taking the offensive. A decade of strenuous effort to disrupt terrorist sanctuaries, take out leaders, pre-empt planning and operations, disaggregate networks, thwart terrorist travel and communications and disrupt fundraising and recruiting is paying off.

And, without question, the drone missile strikes in Pakistan’s tribal areas have helped put al-Qaida on the defensive. Similar operations conducted against an al-Qaida affiliate in Yemen have paid dividends, as well.

The results speak for themselves. Successful terrorist attacks on U.S. targets — both at home and overseas — have declined since 2005.

The efficacy of drone strikes is unquestionable. As an act of war, such strikes also meet the test of proportionality. That is: they employ a level of force consonant with the goal of the operation; the attacks are not indiscriminate; and the operations take reasonable precautions to safeguard the lives of innocents.

That said, drone strikes alone can’t and won’t win this war. And a war plan built principally around playing whack-a-mole with terrorist leaders will likely create more problems than it solves.

That’s worrisome, because under President Barack Obama’s counterterrorism strategy, that appears to be the path he intends to follow in fighting the long war.

Obama has embraced a “small footprint” strategy for overseas operations, relying primarily on Special Forces operations, covert action and strikes with unmanned aerial vehicles.

Without persistent presence and engagement in and around the terrorist’s home ground, the United States will lack the real-time actionable intelligence necessary to target terrorists effectively and to suppress insurgencies successfully.

Without that presence and engagement, drone strikes increasingly will become shots in the dark — missing their targets, killing the wrong people and inflaming local animosity.

What’s worse, people who only see the American presence as a sudden fireball in their neighborhoods will have little incentive or motivation to take sides against terror. Worst of all, Obama’s “new and improved” strategy ignores the real problem.

Al-Qaida is not simply another terrorist group. Osama bin Laden’s gang trained thousands of mujahidin during the 1990s and spread them throughout the Muslim world for a reason — and it wasn’t just to conduct 9/11s.

Al-Qaida seeks to co-opt or gain control of Islamist groups around the globe. It has been building a global insurgency. Drone strikes can be a successful tactic for hunting down the leaders of terrorist groups, but attrition alone is counterproductive when combating an insurgency.

The prospect of “body counts” as the proper metric for measuring success should give Americans pause. Battling an Islamist insurgency requires more than just more missile strikes.

First and foremost, it requires persistent U.S. engagement in the world’s trouble spots — not just parachuting in, lobbing a missile at the problem and heading for home.

U.S. presence may not always mean boots on ground or bucketfuls of foreign aid, but it does mean conducting a range of activities that include economic, political and diplomatic action — and, sometimes, a more muscular military response.

The U.S. does not have to act as the world’s policeman. Even it wanted to, that’s too big a job for any one nation. But, it can’t safeguard its place in the world by just being a global sniper, either.

America has interests around the planet. If it wants to safeguard them and protect the homeland from enemies who roam far from our shores, America must commit all the resources necessary. Drone strikes are a reasonable and efficacious part of what must be done. But they are only a small part.

James Jay Carafano is director of the Allison Center for Foreign Policy Studies at the Heritage Foundation.