"Even in the absence of a nuclear attack against our country, no one can tell the president 'no,'" one senator said.
For the first time in over 40 years Congress held a hearing about the authority of the president to launch nuclear weapons, and three Democratic senators were very upfront about their thoughts.
While the majority of the senators at the Senate Foreign Relations Committee avoided directly mentioning President Donald Trump by name, instead choosing to talk about a president's authority in general, Sens. Chris Murphy, Ed Markey, and Jeanne Shaheen had no problem either directly referring to him, or naming him outright.
Murphy, from Connecticut, was the first to directly talk about Trump.
"Let me just pull back the cover from this hearing. We are concerned, that the president of the United States is so unstable, is so volatile, has a decision making process that is so quixotic, that he might order a nuclear weapons strike that is wildly out of step with US national security interests," he told the testifying witnesses as he started his line of questioning.
"So let's just recognize the exceptional nature of this moment and the discussion we are having today."
The committee spoke with retired US Air Force Gen. C. Robert Kehler; Peter D. Feaver, a professor of political science at Duke University; and Brian McKeon, who formerly acted as the undersecretary for policy at the Pentagon.
Congressional approval is required for the use of conventional military force, but nuclear powers remain firmly under the grip of the president and have since the dawn of the nuclear era.
Throughout the panel, both the experts and senators distinguished between a preemptive strike by the US and a reactive strike to the US being attacked.
Sen. Bob Corker, the head of the foreign relations committee and one of Trump's most vocal critics among Senate Republicans, pushed back at the perception that the hearing was organized to criticize the current president.
"This is not specific to anybody," Corker, a Tennessee Republican, said.
Markey, from Massachusetts, started his time by saying that nuclear weapons are "for deterrence not war fighting," and that "absent a nuclear attack upon the United States or our allies, no one human being should have the power to unilaterally unleash the most destructive forces ever devised by human kind."
He quickly followed that up by saying "I fear that in the age of Trump, the cooler heads and strategic doctrine that we once relied upon as our last best hope against the unthinkable seem less reassuring than ever."
On the issue of the President being able to start a nuclear war, he was very direct; "Even in the absence of a nuclear attack against our country, no one can tell the president 'no.' Not Secretaries Mattis, or Tillerson. Even General Kelly, the president's chief of staff, can't control the president's Twitter tantrums."
"As a result," Markey said, "many Americans share my fear that the president's bombastic words could turn into nuclear reality."
Other senators also focused on Trump's use of Twitter, especially his ongoing tweeted attacks at North Korean leader Kim Jong Un.
Shaheen, from New Hampshire, echoing concerns from Maryland Sen. Ben Cardin, followed, saying "we are dealing with a president ... who has not seemed to be willing to accept advice on many issues affecting power."
She said that if the president had to act, she wanted the president to act "in a way that acknowledges input from a lot of experts and not to act based on a Twitter post."
The comments struck at the heart of the reason the hearing took place. Many people, government officials and civilians alike, have been worried about the possibility of President Trump unilaterally taking the country into a nuclear war.
Alex Lockie contributed to this story.