Read Defense Secretary Jim Mattis' full resignation letter to Trump

Jim Watson/Pool Photo via AP

U.S. Secretary of Defense James Mattis addresses a press conference with his Norwegian counterpart Frank Bakke-Jensen, at the Ministry of Defense in Olso, Norway, on Saturday, July 14, 2018.

• Secretary of Defense Jim Mattis is stepping down, and his resignation letter released on Thursday offers some insight about what motivated his decision.
• "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," he continued.
• Read the full letter below.

Secretary of Defense Jim Mattis is leaving the White House - and his resignation letter released to news organizations on Thursday give insight into why.

"My views on treating allies with respect and also being clear-eyed about both malign actors and strategic competitors are strongly held and informed by over four decades of immersion in these issues," Mattis, a retired four-star Marine Corps general wrote. "We must do everything possible to advance an international order that is most conducive to our security, prosperity and values, and we are strengthened in this effort by the solidarity of our alliances."

"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," he continued. The full letter can be read below:

According to the letter, Mattis will leave his post on February 28, 2019, "a date that should allow sufficient time for a successor to be nominated and confirmed," he wrote in his letter. Mattis served for 44 years in the US Marine Corps, and in his letter he expressed his appreciation for "this opportunity to serve the nation and our men and women in uniform."

Read more: Defense Secretary Jim Mattis quits, says his views aren't 'aligned' with Trump as president upends major US policies

On Thursday, President Donald Trump tweeted that Mattis was "retiring, with distinction, at the end of February."

"General Jim Mattis will be retiring, with distinction, at the end of February, after having served my Administration as Secretary of Defense for the past two years. During Jim's tenure, tremendous progress has been made, especially with respect to the purchase of new fighting equipment," Trump said in a tweet. "General Mattis was a great help to me in getting allies and other countries to pay their share of military obligations. A new Secretary of Defense will be named shortly. I greatly thank Jim for his service!"

The announcement about Mattis leaving his post comes one day after Trump announced a withdrawal of troops from Syria on Wednesday, a decision that allegedly surprised the Pentagon and drew ire from Republican lawmakers on Capitol Hill.