Read this and answer the question. If the question is unanswerable, say "unanswerable".

In the American Old West, policing was often of very poor quality.[citation needed] The Army often provided some policing alongside poorly resourced sheriffs and temporarily organized posses.[citation needed] Public organizations were supplemented by private contractors, notably the Pinkerton National Detective Agency, which was hired by individuals, businessmen, local governments and the federal government. At its height, the Pinkerton Agency's numbers exceeded those of the United States Army.[citation needed]

Which military branch helped the Old West's inadequate local police?
The Army