While the 1973 War Powers Act requires a President to get the approval of Congress before using the force of nuclear war 60 days before launching, according to a Brookings Institute report, the rule doesn’t matter. The report stated, “A nuclear war could easily devastate the planet within just days or hours—long before the 60-day stipulation would be binding. Even if a President had obtained congressional approval for a war that began using only conventional weapons, no provisions of the War Powers Act would require subsequent congressional action prior to nuclear escalation.”
Also, since the 1940s, the US has had a “first strike” policy where they don’t need to wait for an attack to launch a nuclear strike. Since the last strike, US military strategists have worked diligently on plans to start a nuclear war in response to attacks from countries like Western Europe and Russia. President Barack Obama hasn’t altered the policy. Donald Trump has expressed a desire to expand US nuclear force, tweeting on December 22, 2016, “The United States must greatly strengthen and expand its nuclear capability, until such time as the world comes to its senses regarding nukes.” Additionally, he has said that, while he would “never, ever” rule out using the weapons, they would be “the absolute last step.”
