The F-22 Boondoggle

The Air Force wants more of these extremely expensive planes, but the whole thing is totally unnecessary. But, hey, it's not like we have any kind of security-related missions ongoing that require large numbers of a completely different kind of military and diplomatic resources so why worry about this stuff? And of course beyond the pure waste of funds, there's the risk of a self-fulfilling prophesy. The more we give in to defense contractors and build pointless weapons systems while yelling "China threat! China threat!" the more likely it becomes that people in Beijing are going to start saying "holy crap, look at this giant anti-Chinese defense build-up the Americans are undertaking" then you've got arms races, mutual suspicion, regional conflict, etc. It's all bad news.

Unless you make very expensive military aircraft for a living, that is, in which case it's great.