Fifty top national security officials from Donald Trump’s own party don’t want you to vote for him.

The officials — who served in previous Republican administrations, including that of George W. Bush — recently signed a letter, published by the New York Times on Monday, essentially describing Trump as a national security threat. Here’s one particularly scathing section:

From a foreign policy perspective, Donald Trump is not qualified to be President and Commander-in-Chief. Indeed, we are convinced that he would be a dangerous President and would put at risk our country’s national security and well-being. Most fundamentally, Mr. Trump lacks the character, values, and experience to be President. He weakens U.S. moral authority as the leader of the free world. He appears to lack basic knowledge about and belief in the U.S. Constitution, U.S. laws, and U.S. institutions, including religious tolerance, freedom of the press, and an independent judiciary.

These claims aren’t exaggerations. In just the past month, Trump has defended his Muslim ban by attacking the family of a fallen veteran. He suggested that he would be open to essentially letting the US military alliance of NATO collapse. He told Republican Congress members that he’d defend a nonexistent article of the Constitution. And so on.

For national security officials, the possibility that someone who said all of these things could become president is a terrifying possibility — and, as they write, a threat to the US.

Read the full letter below:

Watch: Donald Trump’s threat to dismantle America’s strongest alliance, explained