When Should the U.S. Invade Other Countries?

In this debate, Jan Ting, professor of law at Temple University, and Bryan Caplan, professor of economics at George Mason University, discuss whether war is ever justified. Prof. Ting argues that while war should be a last resort, there are occasions where the consequences of not going to war outweigh the costs of war. He uses World War II as an example in which war prevented great evil. Prof. Caplan argues for strict pacifism, saying it is highly unlikely that any benefits of war would outweigh the horrific costs.
In this clip, Prof. Caplan argues that there are a number of cases in the world that involve ideological or religious thinking contradictory to our notion of human rights and dignity that we would not invade. For example, we would not invade Saudi Arabia if they refuse to give women equal rights, even though we disagree with the practice. We would not invade China if they don’t become a democracy.
Prof. Ting agrees that we should have an aversion to intervention, but that we need to have the option on the table to deal with situations like we saw in Nazi Germany. Prof. Caplan counters, saying, “It seems like really all that you’re saying is even though we have a lot of evidence that our best thinking isn’t very good, let’s do it anyway and rely on it. . . . Saying we’re going to go and attack a country and kill a lot of innocent people when we just have a guess that it might be better is not good enough.” What do you think?