The tide of defections by leading moderate Republicans to the camp of Democratic Party presidential candidate Joe Biden has become a wave.

Seventy-three former national security officials from four Republican administrations and former GOP senators and congressmen in the United States Congress announced their endorsement of Biden the past week. They join a growing number of other Republican leaders led by former Ohio governor John Kasich, who have endorsed Biden while repudiating Trump.

The 73 national security experts banded together as a group called the "Former Republican National Security Officials for Biden." This group consists of high-level officials from the Trump, George W. Bush, George H.W. Bush and Ronald Reagan administrations.

They released their stunning statement of support for Biden in a full-page ad in the Wall Street Journal published Friday. Their statement came a day after Biden accepted his party's nomination as presidential candidate on August 20.

The 10-point letter both strongly endorsed Biden while severely condemning Trump as a grave threat to the national security of the United States. In sum, the signatories collectively assert Trump has "gravely damaged America's role as a world leader." Trump has shown he is unfit to lead during a national crisis. He also solicited foreign influence from Russia and undermined the public's confidence in the U.S. presidential elections.

Like all Americans, the signatories to the statement had hoped Trump would govern wisely. This has not been the case. Instead, Trump has disappointed millions of voters who put their faith in him. Worse, Trump has demonstrated he is dangerously unfit to serve another term.

"In contrast, we believe Joe Biden has the character, experience, and temperament to lead this nation," said the group. "We believe he will restore the dignity of the presidency, bring Americans together, reassert America's role as a global leader, and inspire our nation to live up to its ideals."

Among the leading moderate Republicans who signed the letter are former NSA and CIA Director Gen. Michael Hayden, former Deputy Secretary of State and Director of National Intelligence Ambassador John Negroponte, former CIA and FBI Director William Webster and former Department of Homeland Security chief-of-staff under Trump, Miles Taylor.

Former members of Congress who signed the manifesto include Reps. Jim Kolbe of Arizona, Jim Leach of Iowa and Christopher Shays of Connecticut.

The 73 join a band of their GOP brethren that have repudiated Trump. Apart from Kasich, this group includes former New Jersey governor Christine Todd Whitman, former New York Rep. Susan Molinari, Bush administration Secretary of State Colin Powell, former Arizona senator Jeff Flake and former Hewlett Packard CEO Meg Whitman.