Acting Secretary of Defense Patrick Shanahan replaced James Mattis late Monday and vowed to work with President Donald Trump to advance his agenda after his predecessor professed his views weren’t totally aligned with the president.

Trump announced the leadership change Dec. 23, just three days after Mattis submitted his letter of resignation and announced his plan to serve through February. Mattis wrote Trump reserves “the right to have a Secretary of Defense whose views are better aligned with yours on these and other subjects.”

I am pleased to announce that our very talented Deputy Secretary of Defense, Patrick Shanahan, will assume the title of Acting Secretary of Defense starting January 1, 2019. Patrick has a long list of accomplishments while serving as Deputy, & previously Boeing. He will be great! — Donald J. Trump (@realDonaldTrump) December 23, 2018

Mattis decided to leave his post after clashing with Trump and his plan to begin pulling American troops from Syria, but Shanahan’s Tuesday statement reads with a slightly more agreeable tone.

“I now look forward to working with President Trump to carry out his vision alongside strong leaders including the service secretaries, the Joint Chiefs of Staff, the combatant commanders, and senior personnel in the Office of the Secretary of Defense,” Shanahan said.

Welcome back from the holidays, @DeptofDefense! In 2019, the National Defense Strategy remains our guide. America’s military strength remains our focus. pic.twitter.com/nm5wesx7et — Acting SecDef Pat Shanahan (@DepSecDef) January 2, 2019

“It is an honor to work with such a dedicated team committed to the greatness of our nation,” he added.

Shanahan, a former Boeing Co. executive, is confronted with the Syria pullout, a move that drew bipartisan hysteria. (RELATED: Obama’s Syria Ambassador Backs Trump’s Decision)

Republican Sen. Lindsey Graham of South Carolina, a usual Trump ally but opponent on this issue, signaled Sunday that Trump is re-evaluating his rapid troop removal.

“I think we’re slowing things down in a smart way,” Graham told reporters outside the White House after meeting with the president. “But the goal has always been the same: To be able to leave Syria, to make sure ISIS never comes back, our partners are taken care of and Iran’s contained.”

Mattis delivered a final message to the military Monday before handing the reins over to Shanahan, advising his fellow Department of Defense employees to “keep the faith in our country and hold fast, alongside our allies, aligned against our foes.”

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