Should the US sometimes pursue realpolitik and sometimes human rights?
In other words is it acceptable for the u.s to sometimes do anything even support dictators, if it is good for the nation, and sometimes Persue moral principles when it can reasonably do so?
There is really no other choice. There are certainly times when the US cannot afford to do anything but engage in realpolitik. For example, it would certainly be better morally if North Korea's dictatorship were destroyed and its people allowed to live freely. But there is no possible way that we can make that happen without causing the death of thousands of people and so we do not.
On the other hand, when we can pursue a more idealistic policy, we should. When we can help another country or when we can do something that is morally right like giving the Panama Canal back to Panama, there is no reason not to.
It would be nice if we could always act on principle, but that is simply impossible.