It doesn't win wars, but it provides the necessary equipment for carnage and stalemates all over the globe. Remember war is just a pretext, the objective is always profit, so as long as a lost war is very profitable it's a success in their books.
IMO the last real war the US participated in and helped to win was WW2 giving it a massive ego. And even then it was drawn in via Pearl Harbor. After that it was a bunch of "wars" it fabricated to satisfy its ego with various (often poor) outcomes.
As long as the profits of weapons contractors go up, it's considered a win. Most senate members are well invested, so they agree...