The US is planning on having lasers as weapons. Nanotechnology plays a huge role in lasers and that means that nanotechnology will help in warfare. Right now most people are thinking of ballistic missiles and other nuclear weapons because they can destroy massive amounts of land. The good things about laser technology are that they can stun or deactivate something without killing it. With missiles, everything gets blown up and no peace can be reached. This means that if a tank was coming to attack, people with laser technology could deactivate the tank without killing the people inside so that war will be less deadly.
The reason why some governments are trying to do this is that they do not want to harm people with war. China is leading with making nanotechnology so they could have the upper hand in future wars. Other places that are trying to get more nanotechnology in war are Mexico, India, Iran, and Thailand.