Suddenly, the media are in a meltdown after "Mad Dog" Mattis announced his departure from the Cabinet after President Trump announced our departure from Syria:

Defense secretaries come and go. President Obama had four of them in eight years, who had some unkind things to say about his leadership or lack of it. There was no talk of chaos or of the only adult in the room leaving.

Foreign Policy Pentagon reporter Lara Seligman wrote the press corp [sic] is contemplating suicide over Mattis' resignation, "I think I speak for all national security reporters tonight when I say I'm about ready to jump off a cliff. But at least I already wrote the "who will replace Mattis" story two months (only two months?????) ago[."]

Democrats who won't defend our southern border and who slept as Obama drew red lines with vanishing ink worry about an ISIS Obama created by a precipitous withdrawal from Iraq regaining strength and reforming in Syria and Iraq. The general Obama fired is suddenly a man of principle whose leadership was indispensable:

House Speaker-designate Rep. Nancy Pelosi (D-CA) said she was "shaken and "concerned". "General Mattis was a comfort to many who were concerned about the path the Trump Admin would choose to take. His resignation letter is defined by statements of principle – principles that drove him to leave the Administration. All of us should be concerned at this time."

There was no such concern when Obama relieved Mattis as commander of CENTCOM without so much as a phone call, a factoid typical of Obama's disdain for the military, its missions, and its heroes.

[Thomas E.] Ricks says Mattis was fired because: Pentagon insiders say that he rubbed civilian officials the wrong way – not because he went all "mad dog," which is his public image, and the view at the White House, but rather because he pushed the civilians so hard on considering the second- and third-order consequences of military action against Iran. Some of those questions apparently were uncomfortable. Like, what do you do with Iran once the nuclear issue is resolved and it remains a foe? What do you do if Iran then develops conventional capabilities that could make it hazardous for U.S. Navy ships to operate in the Persian Gulf? He kept saying, "And then what?" There is also a belief that Mattis and Obama differed on Iran. "A particular point of disagreement was what to do about mischief Iran is exporting to other countries. Mattis is indeed more hawkish on this than the White House was," writes Ricks in yet another post.

Mattis is probably more hawkish than Trump as well. Mattis and Trump disagree on strategy. Obama and Mattis disagreed on goals and consequences. While a liberal uproar greeted the former, utter silence greeted the latter.

No doubt, our Syrian withdrawal was a factor in Mattis's decision. I don't agree with it, but to compare it with Obama's withdrawal from Iraq when he snatched defeat from George W. Bush's victory, as many conservatives are doing, is a tad disingenuous.

President Trump destroyed the ISIS caliphate as originally constituted in Syria and Iraq. Obama watched it grow and facilitated its growth through inaction and indifference. ISIS is a cancer that has spread but is currently in remission. If it comes back in force, we can deal with it. But it is not dangerous isolationism for Trump to consider Iran the main threat and to focus on it.

It is Iran that wants its nukes to be an existential threat to Israel, Europe, and the United States. It is Iran that is trying to build a corridor of terror from Tehran through Syria and Iraq to its Hezb'allah puppets in Lebanon.

Iran is the head of the snake. Syria and ISIS are the tail. Strike at the head, and you kill the snake. President Trump is doing that by nixing Obama's nuclear deal and reimposing sanctions, including prohibitions on Iranian oil exports. That, arguably, is a better way to deal with a very real threat than chasing random jihadis through the Syrian desert.

Critics of our Syrian withdrawal forget that under President Trump, American-backed forces liberated the ISIS capital of Raqqa. They forget the hundreds of Russian mercenaries killed in clashes with U.S. forces. They forget the cruise missile strikes against Syrian targets under the nose of Vladimir Putin. Trump's moves in Syria were hardly under a white flag.

Obama, by contrast, didn't want to win anywhere and waged his own war against the U.S. military, purging it of generals, admirals, and commanders who dare to talk of victory. President Obama began a military purge not dissimilar to those routinely conducted by third-world despots, with the goal of eliminating voices that might oppose his withdrawing from the world stage. As Investor's Business Daily editorialized:

[W]hat has happened to our officer corps since President Obama took office is viewed in many quarters as unprecedented, baffling and even harmful to our national security posture. We have commented on some of the higher profile cases, such as Gen. Carter Ham. He was relieved as head of U.S. Africa Command after only a year and a half because he disagreed with orders not to mount a rescue mission in response to the Sept. 11, 2012, attack in Benghazi[.] ... From Breitbart.com's Facebook page comes a list of at least 197 officers that have been relieved of duty by President Obama for a laundry list of reasons and sometimes with no reason given.

Retired four-star general and Fox News analyst Jack Keane, architect of the Iraq surge that produced the victory Obama threw away, recently spoke on Kilmeade and Friends about Obama's ongoing purge of the military of officers who oppose his isolationist and defeatist policies.

It's also a fact that a number of our general officers, not all of them but a number of them, were asked to leave before what would normally be accepted as the routine tenure for that particular position, and General Mattis is a case in point who had very strong views on Iran. Most of us agree with those views but I know the administration did not agree with them. General Flynn, who you know very well and had on your show, was an outspoken proponent for understand[ing] radical Islam, how dangerous this particular threat was and was trying to communicate that, he was not able to serve out his full tenure. So yes, that's another fact that we can substantiate, that there were generals who did leave earlier than what their tenure would be and the characteristic they all shared together is they did disagree with the administration on various points."

General Mattis is an old-school warrior known for his colorful rhetoric and his commitment both to his men and to his mission. He, along with other generals like David Petraeus and Stanley McChrystal, did have a problem with Obama's quest for a substitute for victory in Iraq and Afghanistan.

As the New York Post reported:

Officially, the administration offers a nothing-to-see-here explanation for Mattis' departure, noting that his tenure in the crucial job was about average for the post. Maybe. But politics is at play here as well. The brusque Mattis apparently fell afoul of National Security Adviser Tom Donilon, an Obama apparatchik. Why? Because Mattis says things the Obama team doesn't want to hear, especially about what might well become the next theater of operations – Iran.

Okay, maybe Mattis was saying things Trump didn't want to hear about tactics and strategies, but we have only one commander-in-chief at a time, and the one we have now is trying to rebuild the military, so we can win wars, not letting the military atrophy while generals who want to win are purged.

We have not only ISIS jihadis to worry about. We have the Iranian nuclear threat, an expansionist China with sub-launched nuclear missiles capable of hitting U.S. cities, and a belligerent Russia developing hypersonic missiles we might not be able to stop as it negotiates with a crumbling Venezuela to base its nuclear-capable bombers on an island not far from Caracas.

So chill out, Chicken Littles of the left and right. There is an adult in the room. His name is Donald J. Trump.

Daniel John Sobieski is a freelance writer whose pieces have appeared in Investor's Business Daily, Human Events, Reason Magazine, and the Chicago Sun-Times among other publications.