On Thursday, Trump offered two tweets on the Barcelona terrorist attack.

The first was Trump at his best: direct but heartfelt: "The United States condemns the terror attack in Barcelona, Spain, and will do whatever is necessary to help. Be tough & strong, we love you!"

The second tweet was idiotic.

There's a lot wrong with that tweet. First, as Caitlin Yilek reports, the General Pershing story is a "tall tale." It pertains to Pershing's supposed execution of Filipino Muslim separatists via bullets drenched in pig blood. Trump likes this story because Muslims regard pork as an unclean food. He believes that if Muslim terrorists are killed with pig blood bullets, their compatriots will give up the fight. The opposite is true.

Yet aside from its likely untruth, the Pershing parable is also unpleasant in that it involves killing unarmed prisoners. Don't get me wrong, I'm not terribly concerned about terrorists' rights, but the U.S. occupation of the Philippines involved a number of atrocities against civilians and was not one of our nation's finer moments.

Trump's thesis has another problem. By preaching Pershing's parable as textbook counter-terrorism, Trump shows his lack of historical knowledge.

Consider that the most significant U.S. counter-terrorism success was the 2006-2010 defeat of Al Qaeda in Iraq. But that success wasn't earned with pig's blood. Instead, it was the result of a multi-pronged U.S. strategy across Iraq. One of the key elements of that strategy was the U.S. Military's earned support from the Anbari tribes of western Iraq. Until late 2006, those tribes had yielded to AQI rule and accepted its attacks on the U.S. Military and the Iraqi government.

But when the U.S. Marines won the respect of tribal leaders, the tribes revolted against AQI. At the same time, the U.S. Army led efforts to restore basic security in predominantly Sunni neighborhoods in and around Baghdad. That meant young men abandoning AQI and supporting U.S. efforts to deconstruct the terrorists.

For a time (until President Barack Obama withdrew U.S. forces from Iraq at the end of 2011), the U.S. government was able to help Iraq develop a functioning economy and greater political reconciliation.

Regardless, the key point here is that this success resulted from a strategy that is the antithesis of Pershing's parable.

The silliness of Trump's tweet isn't just proved by the campaign against al Qaeda. It is proved by the ongoing campaign against the Islamic State. Today, the U.S. government that Trump leads is fighting ISIS with a particular dedication towards minimizing civilian casualties. The intention is to destroy the terrorist empire while mitigating the growth of grievances that might allow it to rise again.

But were Trump to have his way; and start rounding up and executing Sunni men on the streets, he would be doing ISIS a great favor. In those atrocities, the brothers, fathers, and sons of the dead would quickly join ISIS to avenge their loved ones.

Ultimately, Trump's tweet makes him look like a fool. At moments of crisis, foreign allies expect measured and confident American leadership which projects certainty we have their back. They do not want to see the President of the United States treating counterterrorism like a game of Call of Duty. Trump's first tweet was pitch perfect, his second tweet was a disaster.

I hope Gens. Dunford, Mattis, McMaster, and Kelly tell him as much.