A day after President Donald Trump ordered the surprise withdrawal of U.S. military forces in Syria, Defense Secretary James Mattis submitted his resignation as Pentagon chief, telling the President in a letter that Mr. Trump deserved someone who agreed with his foreign and defense policies.

"Because you have the right to have a Secretary of Defense whose views are better aligned with yours on these and other subjects, I believe it is right for me to step down from my position," Mattis wrote in a letter that clearly rebuked the President's world view.

"While the US remains the indispensable nation in the free world, we cannot protect our interests or serve that role effectively without maintaining strong alliances and showing respect to those allies," Mattis wrote.

The Mattis resignation came as multiple news organizations were reporting that President Trump had ordered the Pentagon to develop plans to withdraw U.S. troops from Afghanistan.

In a tweet, President Trump had cast the decision as one where Mattis decided to retire. Lawmakers on Capitol Hill saw it differently, as they saluted Mattis, and bemoaned his loss from the President's Cabinet.

"We want our enemies to fear us and our allies to trust us. They trusted Secretary Mattis," said Rep. Michael McCaul (R-TX), who told reporters that Democrats also trusted Mattis.

"I slept better at night knowing he was there," McCaul added.

"This is a sad day for America because Secretary Mattis was giving advice the President needs to hear," said Sen. Ben Sasse (R-NE).

"This is scary," said Sen. Mark Warner (D-VA). "Secretary Mattis has been an island of stability amidst the chaos of the Trump Administration."

"This is bad news for the nation and the security of the world," said Rep. Will Hurd (R-TX).

"Those of us who urged Defense Secretary Mattis to weather the White House storm knew that every honorable man has a principled limit," said Sen. Dick Durbin (D-IL).

The departure of Mattis is the latest high profile job which the President needs to fill, including Attorney General, Interior Secretary, and possibly other Cabinet posts as well.

Here is the full resignation letter from Secretary Mattis:

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Credit: Jamie Dupree

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Credit: Jamie Dupree

ajc.com

Credit: Jamie Dupree

icon to expand image

Credit: Jamie Dupree

ajc.com

Credit: Jamie Dupree

icon to expand image

Credit: Jamie Dupree

The resignation of Mattis prompted an especially blunt reaction from Senate Majority Leader Mitch McConnell, who expressed his backing for Mattis' support of NATO and other familiar U.S. allies.

"So, I was sorry to learn that Secretary Mattis, who shares those clear principles, will soon depart the administration," McConnell said in a statement.

"But I am particularly distressed that he is resigning due to sharp differences with the president on these and other key aspects of America’s global leadership," McConnell added.

"A Secretary of Defense quitting over a public disagreement with a President whose foreign policy he believes has gone off the rails is a national security crisis," said Sen. Chris Murphy (D-CT).

"No way around it," Murphy added.