Nobody said it's easy. But the last fifty years or so are the first time period were the chances of a successful defense are bigger than zero. We have top men working on it: https://en.wikipedia.org/wiki/Asteroid_impact_avoidance
Right now it isn’t easy or hard, it’s impossible. We probably have the tech, but it would need to be ready to launch on detection. Worse, we have shit detection.
So yes, in theory we could divert some impactors, but in practice right now? No. Nukes don’t help either.
