Deterrence Theory mostly harkens to the Cold War. It maintains that war against a country could be averted if the enemy knew they’d lose the fight. This means a country with nuclear weapons wouldn’t be threatened by another lacking these devices. The Fugs (an early underground-type rock band with Beat poet connections), take it a step further, with this song from 1966, which may be referencing the military strategy of First Strike.
First Strike is when a country attacks another to considerably hamper its ability to fight back, at the time and near future. You may find this referred to as “counterforce” and “pre-emptive nuclear strike.” It’s minor variation includes focusing on the destruction of an enemy’s nuclear facilities. This rationale informed the “removal” of Saddam Hussein whose Iraq was suspected to have “weapons of mass destruction.” We see the same point being reached presently with Iran and North Korea.