It really depends on the situation, but in general I would say that there are times that it is justified for the CIA to launch a military coup against a foreign government. There are times when a government in another country is committing serious crimes against its citizens or others. This is when the CIA should step in and launch a coup.
Although violence should always be a last resort, a coups against foreign governments is sometimes necessary in order to overthrow powerful dictators who regularly oppress their own people and allow them no rights or resources. When the death of a leader results in the health and safety of his people, it is justifiable.
I think if the US government wants to assassinate foreign leaders or orchestrate coups, they should not do it in secret because with secrecy there is no debate, the US public does not get to voice their opinions about it whether its support or criticism because officially it is not happening.
Also a lot of the time they have been overthrowing elected governments to support US financial interest and put in brutal regimes. I doubt many Americans would be for that.