As concerned American taxpayers, we would like to see competitive bidding for the launching of our military satellites. Considering only the United Launch Alliance for such contracts appears irresponsible, especially when far lower prices are asked by SpaceX.
NASA and commercial enterprises regularly use SpaceX, and always successfully. Why not the Air Force?
Innovative SpaceX is the only company capable of returning significant cargo from the ISS. It is seeking to lower costs much further through the development of reusable rockets that land on their tails. Other manufacturers thought that was impossible.
SpaceX's engines are American, while ULA uses Russian engines for its Atlas V rockets. That does not seem in alignment with the current policy of sanctions against Russia.