That was the message Tuesday from an extraordinary, first-time-in-four-decades hearing convened by Senate Foreign Relations Committee Chairman Bob Corker ― who last month said he anxious that Trump could "start World War III" and called the White House an "adult day care center".
Tuesday's hearing reflected the "exceptional nature" of the present context, said Senator Chris Murphy, a Democrat from CT.
Tuesday's hearing marks the first time since 1976 since either the House or Senate Foreign Relations Committees have examined the president's ability to use nuclear weapons.
"I don't think that the assurances that I've received today will be satisfying to the American people", Massachusetts Democrat Ed Markey said. "I think that we have to keep trust, keep faith in the system that we have that has proven effective now for decades".
The witnesses described teams of legal advisors working for the Commander of Strategic Command General John Hyten and in the office of the Secretary of Defense James Mattis who would advise the chain of command on the legality of a hypothetical order to use nuclear weapons.
Brian McKeon, a top Pentagon official under former President Barack Obama, acknowledged under questioning from committee members that an officer in the chain of command who refused to comply with a presidential order would face removal.
Retired Gen. Robert Kehler, who previously headed the U.S.'s command that would be in charge of the nuclear arsenal during a war, said while the US military is obligated to follow legal orders, it is not duty bound to adhere to illegal ones. "But you'd have a real constitutional crisis on your hands if that occurred", he said.
"I don't think that the assurances that I've received today will be satisfying to the American people", said Markey, a Democrat from MA.
Peter Feaver, professor of political science and public policy, will testify in front of the Senate Foreign Relations committee Tuesday.
In August, Mr Trump vowed to unleash "fire and fury like the world has never seen" on North Korea if it continued to expand its atomic weapons programme. Trump wrote on Twitter while on a trip to Asia, using admittedly toned-down rhetoric compared to past statements. "If anyone out there thinks they can somehow get away with something because the politics of the United States would somehow prevent the commander-in-chief from acting expeditiously, that could also encourage miscalculation, particularly on behalf of people who are isolated from the world, don't get a lot of information, and have never had anyone tell them they're wrong or no, and I have one person in particular in North Korea who concerns me in that regard".
"The United States military does not blindly follow orders", he said. Jeanne Shaheen (D-N.H.).
"I would be very anxious about a miscalculation based on continuing use of his Twitter account with regard to North Korea", Mr McKeon said.
Multiple senators argued that the President's loose Twitter finger could have catastrophic consequences. In a September tweet, he warned about North Korean leaders: "They won't be around much longer!" And days after calling on Kim to enter peaceful negotiations, he spoke before South Korea's parliament and listed a litany of alleged human rights abuses against the North Korean leader, calling him a "deranged tyrant" presiding over a "cult". "There are no checks on the president's authority".