Andrew Harrer | Bloomberg via Getty Images
James Mattis, U.S. Secretary of Defense, right, and Patrick Shanahan, Deputy Secretary of Defense, wait outside the Pentagon before an event in Washington, D.C., on Thursday, Aug. 9, 2018.
In his resignation letter, Mattis said that disagreements with the president about America’s treatment of both allies and strategic competitors came from beliefs that “are strongly held and informed by over four decades of immersion in these issues.”
Mattis, a revered Marine with a military career spanning four decades, was known for his battlefield prowess and kinship with rank-and-file service members. Before he became Trump’s Defense secretary, the four-star general led the U.S. Central Command, the combatant command responsible for the wars in Iraq and Afghanistan.
In contrast, Shanahan, if confirmed by the Senate, may head the largest federal agency with limited experience in defense and foreign policy.
However, he is by no means the first Trump appointee to take his cues from the business world and apply them to foreign policy.
Trump himself lacked experience in government, and campaigned on running Washington based on the lessons he learned leading the Trump Organization and promoted as a reality show host on “The Apprentice.”
Trump’s first secretary of State, Rex Tillerson, entered the public sector after serving as CEO of Exxon Mobil. But despite Tillerson’s efforts to streamline the State Department, Trump pushed him out and would later say he was “dumb as a rock and I couldn’t get rid of him fast enough.”
And yet, Shanahan’s entrance into the Pentagon comes at a particularly tumultuous time.
The unpredictable Trump administration has pulled the United States back from global commitments and pushed forward on ambitious projects like the denuclearization of North Korea, a U.S. troop drawdown in the Middle East, a growing military footprint on the southwest border with Mexico and heightened tensions with Iran and Venezuela.
contributed to this report.