The US's developing them -- and especially the US's being the first to develop them -- makes it at least slightly more likely that Russia and China will develop them.
My point was that Russia and China (and France, the UK, and many other nations) are going to develop them anyways, regardless of whether the US develops them.
Anyone who likes living in a world where the US has military superiority over Russia and China (and every other nation) should support the US military, Google, and any other US company developing these weapons.
Anyone who likes living in a world where the US has military superiority over Russia and China (and every other nation) should support the US military, Google, and any other US company developing these weapons.