After what happened in Hiroshima and Nagasaki the world reached an unspoken consensus to not use nuclear weapons. The loss of innocent life, risks, and stakes and the world reaction are just not worth it. The US's problem with Iran is not nuclear weapons, the US will not be satisfied with anything short of regime change in Iran.
Iran can only be a winner with Russia on its side if the relationship they form follows the Israeli-American model. This will never happen.
After what happened in Hiroshima and Nagasaki the world reached an unspoken consensus to not use nuclear weapons. The loss of innocent life, risks, and stakes and the world reaction are just not worth it. The US's problem with Iran is not nuclear weapons, the US will not be satisfied with anything short of regime change in Iran.