Whatever the best campaign contributors say it is.
In the case of space launch capability you would think that truly objective consideration would weigh not only immediate cost factors, but also how critical it is to have certain production capabilities here at home that are not only reliable, but competitive on the world market. You would also want to make sure ask, just because we have policy issues with another country, is it always in our interests to disengage trade wise? Isn't the point of diplomacy to find ways to engage each other in positive ways? And are we sure that not purchasing an item from a particular company punishes the leader of that country more than the people that populate it?
Such objectivity, of course, in our form of marketed government is quite naive. Any more than thinking rationally about much of anything at all would be. No, we just leave it to competitive lobbying and the money that fuels it.