Fifty conservative national security officials explicitly stated their opposition to Donald Trump in a letter on Monday, claiming he "lacks the character, values and experience" to be the nation's next commander in chief.

"None of us will vote for Donald Trump," declared the signatories, many of whom have been vocal critics of the GOP presidential nominee since the primary. "We are convinced that he would be a dangerous president and would put at risk our country's national security and well-being."

According to those who signed the letter, Trump's "lack of understanding of America's vital national interests" has been on full display during the 14 months he has spent on the campaign trail, and he has "shown no interest in educating himself."

"He continues to display an alarming ignorance of basic facts of contemporary international politics," the letter continues. "At the same time, he persistently compliments our adversaries and threatens our allies and friends."

The letter is signed by a handful of former high-ranking government officials, including former CIA director Michael Hayden, who recently said he plans to vote for Hillary Clinton and has described Trump as an "unwitting agent of the Russian Federation;" former Department of Homeland Security Secretaries Michael Chertoff and Tom Ridge; former Deputy National Security Adviser Gary Edson and former Deputy Attorney General Donald Ayer. The letter was also signed by Robert Blackwell and James Jeffrey, both of whom served on George W. Bush's National Security Council during his tenure as president, and John Negroponte, former director of national intelligence.

In addition to questioning his understanding of foreign affairs, the signatories claim Trump lacks key qualities and characteristics that are must-haves in a future president.

"He is unable or unwilling to separate truth from falsehood. He does not encourage conflicting views. He lacks self-control and acts impetuously," the letter states. "All of these are dangerous qualities in an individual who aspires to be president ... with command of the U.S. nuclear arsenal.

Despite their criticism of the Republican presidential hopeful, those who signed the letter noted that they also "have doubts about Hillary Clinton."

"But Donald Trump is not the answer to America's daunting challenges and to this crucial election," they wrote, adding that he would be the "most reckless President in American history."

In March, 121 conservative national security experts signed an open letter in opposition to Trump, and several said they were standing by their convictions after Trump clinched the nomination.

Statement of Former National Security Officials by Mairead McArdle on Scribd