House Speaker Nancy Pelosi told House Democrats in a letter on Friday that she spoke with the Chairman of the Joint Chiefs of Staff Gen. Mark Milley to discuss President Donald Trump and the nuclear codes, as Democrats call for the President to be removed from office after a violent pro-Trump mob stormed the Capitol. “This morning, I spoke to the Chairman of the Joint Chiefs of Staff Mark Milley to discuss available precautions for preventing an unstable president from initiating military hostilities or accessing the launch codes and ordering a nuclear strike,” Pelosi wrote in a letter. “The situation of this unhinged President could not be more dangerous, and we must do everything that we can to protect the American people from his unbalanced assault on our country and our democracy.” After speaking with Milley Friday, Pelosi told her caucus that she has gotten assurances there are safeguards in place in the event Trump wants to launch a nuclear weapon, according to multiple sources on a caucus call. “Speaker Pelosi initiated a call with the Chairman. He answered her questions regarding the process of nuclear command authority,” Colonel Dave Butler said in a statement. LIVE UPDATES: Fallout intensifies over Trump’s response to Capitol riot The announcement from Pelosi comes one day after the House speaker called on Vice President Mike Pence to remove Trump from office by invoking the 25th Amendment and warned that if that does not happen, Congress may pursue impeachment. Since that time, calls from Democrats for the President to be impeached following the insurrection at the Capitol have only grown louder and it is possible the Democrat-led House could move toward a vote to impeach Trump for a second time as early as next week. Pelosi’s letter is once again raising questions about what it takes to actually launch a nuclear weapon and whether military commanders can refuse an order from Trump. Only the President of the United States has the authority to order the deployment of nuclear weapons. But contrary to popular belief, the “nuclear football,” which always accompanies a President does not contain a button. Instead has the equipment and the decision-making papers that Trump would use to authenticate his orders and launch a strike. The decision to launch a strike requires the President to work with military aides possessing the materials he needs to order an attack, as well as personnel at all levels, from top commanders all the way down to service members working in the missile silos. Current and former defense officials have also insisted that the military does not blindly follow orders from the President, noting there are layers of checks and balances intended to safeguard against a President unlawfully ordering a nuclear strike.” But the reality is that the only basis for interfering with a direct order is if it’s illegal, immoral or unethical. And there is a widely held belief among military commanders that they must resign if they are unable to carry out a legal order. Some nuclear experts argue that there is little Milley could do to prevent Trump from ordering a nuclear launch, as he and other top national security officials are not technically in the chain of command when it comes to such decisions. “Any ‘safeguards’ Milley may have erected to effectively prevent Trump from exercising sole authority of nuclear launch would actually be a ‘coup’ by the standard definition,” according to Vipin Narang, a nuclear policy expert and professor at MIT. “The procedure for nuclear launch authority grants POTUS the sole authority to order the launch of nuclear weapons,” he told CNN, adding that, by design, the President is not legally required to consult with or receive assent from any one of a number of people, including the vice president, national security adviser, secretary of defense of chairman of the Joint Chiefs of Staff. “None are, contrary to popular belief, in the nuclear launch chain of command. Therefore any ‘safeguards’ that could effectively prevent POTUS from exercising sole authority to launch nuclear weapons are either illegal or illusory,” Narang added. “So long as Trump remains in office, he retains the legal authority to solely launch some or all of America’s nuclear weapons until 12:01pm on January 20, or until he is removed from office.” The top four congressional leaders – Pelosi, Mitch McConnell, Chuck Schumer and Kevin McCarthy – also spoke Thursday night with Milley and acting Secretary of Defense Christopher Miller about the federal response to the breach of the Capitol building, according to a source familiar. It is unclear if the issue of the nuclear codes came up during that conversation. In the letter sent to Democrats Friday, Pelosi shared the news of US Capitol Police officer Brian Sicknick’s death following the breach, and said that she hopes to hear from Pence “as soon as possible” about the possibility of removing Trump from office through the 25th Amendment. “Nearly fifty years ago, after years of enabling their rogue President, Republicans in Congress finally told President Nixon that it was time to go. Today, following the President’s dangerous and seditious acts, Republicans in Congress need to follow that example and call on Trump to depart his office – immediately. If the President does not leave office imminently and willingly, the Congress will proceed with our action,” Pelosi wrote. Pelosi also said that the attack on the Capitol “had a great traumatic effect on Members and congressional employees,” and said there will be a letter coming from the Office of the Attending Physician and the Office of the Employee Assistance about resources available to members for responding to trauma in the wake of the siege. This story has been updated with additional developments Friday.