Did you enjoy all that time between the announcement of Secretary of Defense James Mattis’s resignation and the Democrats’ politicization of it? I believe it was about five seconds. The news is certainly disappointing. Thanks to the leadership of President Trump and Secretary Mattis, tremendous progress has been made in cleaning up the mess left behind by Barack Obama—most notably against ISIS. In fact, the success in "defeating” ISIS was cited as Trump’s reason for announcing the United States’ withdrawal from Syria. Given Obama’s fumble with Iraq—his premature departure creating a leadership vacuum that ultimately caused the rise of ISIS—I’m not yet convinced that leaving Syria is the best move. Unlike his predecessor, Trump has deferred much of his military strategy to the advice of his generals, but Mattis’s disagreement over this withdrawal and the reduction of troops in Afghanistan was a major reason for his decision to resign.

This latest high-profile departure quickly had Democrats running to the cameras to attack Trump. They’re not alone though. Several Republicans have already expressed concern over the resignation—citing Trump’s disagreements with Mattis in particular.

Let’s be honest here: The departure of a secretary of defense over foreign policy and military strategy differences is hardly a new thing. Obama’s first secretary of defense, Robert Gates, resigned without incident in 2011, but would later criticize Obama’s role as commander in chief in his memoir published a few years later. It revealed a troubled relationship between Obama and the Pentagon:

... Gates – who was first appointed to his post by former President George W Bush – reveals, in a series of swipes that are surprisingly combative coming from such a senior former official, problems between the White House and the Pentagon that have made for troubling relations at the very highest levels.

"All too early in the administration,” adds Gates, "suspicion and distrust of senior military officers by senior White House officials – including the president and vice-president – became a big problem for me as I tried to manage the relationship between the commander in chief and his military leaders.”

Perhaps most damagingly, he also alleges that Obama did not believe in his own strategy for ending the war in Afghanistan, which he was "skeptical if not outright convinced ... would fail,” and that he was skeptical at best about the leadership of the country’s president, Hamid Karzai.

"The president doesn’t trust his commander, can’t stand Karzai, doesn’t believe in his own strategy, and doesn’t consider the war to be his. For him, it’s all about getting out,” writes Gates.

In 2013, Obama’s second secretary of defense, Leon Panetta, resigned after less than two years on the job over frustrations with Obama. Panetta also wrote a memoir revealing disturbing details about his time in the Obama administration, and told of Obama’s repeated decisions to ignore his advice, citing specifically "the withdrawal of all troops from Iraq in 2011, the failure to intervene in Syria’s civil war by arming rebels and the abrupt reversal of Mr. Obama’s decision to strike Syria in retaliation for using chemical weapons on civilians.”

In 2014, shortly after the midterm elections that saw Republicans take control of the U.S. Senate, Barack Obama fired Secretary of Defense Chuck Hagel over, you guessed it, policy and strategy disagreements. Hagel said in an interview a year later that the Obama White House tried to "destroy” him and that they had no strategy for fixing Syria.

More disturbing than anything that has come out thus far regarding Mattis’s resignation is that Obama’s fiercest critics of his foreign policy and military strategy have been his secretaries of defense. In April 2016, all three of Obama’s former secretaries of defense at the time—Gates, Panetta, and Hagel—blasted Obama in interviews for a Fox News special called "Rising Threats, Shrinking Military.”