“While Congress or military leaders are involved in any other decision to use of military force, the president can legally order a nuclear strike on his own. “Congress doesn’t have any role in this at the moment,” says Alex Wellerstein, a historian of science at the Stevens Institute of Technology. “They’re not expected to be consulted.”
Unitary presidential control of nuclear weapons dates from the immediate aftermath of the Hiroshima and Nagasaki bombings, and the practice has been cemented over time. This is partly a product of the general shift toward a stronger executive, and partly just an issue of timing: If the missiles are coming, you can’t call up Congress.”
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“”The system we have is very much a product of the 1940s, with some modifications in the 1950s and the 1960s,” Wellerstein says. “And we don’t live in the 1940s, ’50s, or ’60s. So I think we should feel free to question whether the system we have now is the ideal system for our present day.””