We might have to pulverize an asteroid before it hits the United States (or some other part of the world)...
Or capture it, park it at an L5 point and MAKE a Space Command office out of it.
No, you don’t want to pulverize them because that can turn one big one into what amounts to cosmic buckshot. Its better to just steer them off course away from us either by using a small nuke(but launch one is risky) or using a high powered laser to cause it to be redirected.
With enough advance warning a small robotic spacecraft could intercept it at a distance and give it a nudge away from our orbit. The problem is that many of the NEOs are not seen until they are too close for an adequate response.