History is not a subject in which causes can be determined with certainty. Any time Historian A says Cause 1 was important, it's possible for Historian B to say, no, that was trivial, it was Cause 2 instead.
Now if you want specific examples where the cowboy role could influence policy, there are obvious things to choose from. Alaskan oil-drilling for example: if your self-image is as a frontiersman, you're more likely to want to explore and exploit the frontier. The disbanding of the Iraqi army is another example: co-opting them would have been the pragmatic thing to do given the lack of stabilizing manpower. But cowboys and sheriffs defeat their enemies, they don't co-opt them (unlike Robin Hood after he beat Little John at quarterstaffs, for instance).
But there's not much point me naming a bunch of instances. There are very many to choose from, and you're just going to say "oh no it isn't" to each one. Possibly you're on the far-Realist edge of the Realist-Idealist spectrum.--"Everything is vague to a degree you do not realize till you have tried to make it precise." -- Bertrand Russell[ Parent ]