"They will be met with fire and fury like the world has never seen".
"Literally nothing has happened in the last 201 days to increase the overall power of the USA nuclear arsenal", Schwartz said.
"The president alone has the authority to launch nuclear weapons, the only restraint being the advice of senior advisors who might be present at the time of crisis, and Donald Trump has shown repeated contempt for informed and wise counsel", he continued in the letter.
The former senator also hit out at the president's rhetoric on North Korea over the past few days, which he said was exacerbating tensions between the two nations. Trump's heated rhetoric comes as his secretary of state seeks to downplay the words.
That's what some Twitter users, including actor and former Barack Obama aide Kal Penn, are demanding, after President Trump tweeted Friday morning that U.S. "It is now far stronger and more powerful than ever before".
The tweet came as Trump traded escalating threats with North Korea.
Washington has warned it is ready to use force if needed to stop North Korea's ballistic missile and nuclear programmes but that it prefers global diplomatic action, including sanctions. Lindsey Graham says Trump isn't going to just "contain the threat".
She went to argue that 'the first scenario is folly, but a United States decision to start a pre-emptive war on the Korean Peninsula, in the absence of an imminent threat, would be lunacy'. But he says that, until that happens, the U.S. Another included a video clip of Trump vowing to respond to North Korean threats with "fire and fury".
Democrats in Congress, led by Rep. John Conyers Jr., sent a letter to Secretary of State Rex Tillerson on Wednesday warning the administration that it would need congressional approval for any preemptive attack on North Korea.
The announcement Thursday warned that the North is preparing a plan to fire four of its Hwasong-12 missiles over Japan and into waters around the tiny island, which hosts 7,000 USA military personnel on two main bases and has a population of 160,000.
Earlier on Wednesday, North Korea said it was "carefully examining" a plan to strike Guam, which is home to about 163,000 people and a USA military base that includes a submarine squadron, an airbase and a Coast Guard group.
He insisted that nothing has changed over the past 24 hours that would make a military response to the dispute more likely adding that "the American people should sleep well at night".
North Korea said it was "carefully examining" a plan to strike Guam, which is home to about 163,000 people and a USA military base that includes a submarine squadron, an airbase and a Coast Guard group.style="text-align: center;"