The U.S. defense department has plans in place to deal with North Korean aggression, but they're not going to make their plans public. And President Trump, knowing what the plan is, can afford to take his "tough talk" approach. The idea is that it's better to bring things to a head now than to kick the can down the road to a time when the North is better prepared. Previous Presidents didn't deal with the problem effectively, so now President Trump has to deal with it.