That would be anyone's guess. There are only two nations with the capability to launch a missile that can reach the US are Russia and China, and only Russia could do more than hit the west coast.
There is also the philosophy of MAD (Mutually Assured Destruction) that was invented by American politics to consider. Not that the current president would be insane enough to commit to a nuclear response (that would potentially initiate nuclear Holocaust), but the military response would border on genocidal.
US weren't effected by the Nuclear Weapons, They created it.
the u.s. used non nuclear weapons and nuclear weapons against japan
The US no longer makes nuclear weapons, it only refurbishes existing ones that are wearing out.
Russians do not know how to use nuclear weapons
All of them have nuclear weapons cause they are the United States.
The US has refrained from using nuclear weapons due to the catastrophic human and environmental consequences associated with their use. Additionally, the world community, including the US, has generally upheld international agreements and norms that seek to prevent the use of nuclear weapons.
no
The US was the first to start testing nuclear weapons
Nuclear weapons are a good thing for the United States because they prevent others from using nuclear weapons on the US. In general, the world would probably be a better place without nuclear weapons if it weren't for the fact that they lead to research in all fields of Nuclear Engineering, like Nuclear Power plants and Nuclear Physics. Since nuclear weapons already exist in the world, for the US to get rid of their nuclear weapons would be unwise. Countries that dislike nuclear weapons or even radical terrorist cells and organizations would now have no reason not to launch a nuclear warhead at the US since no retaliation would occur. The strategy of nuclear weapons preventing others from using them against the US is called the Deterrent Strategy.
All the facilities used by the US to prepare the materials for nuclear weapons, build nuclear weapons, design and test new nuclear weapons. This is all lead by the Department Of Energy.
The U.S used no nuclear weapons whatsoever on Vietnam.
no