Julian Zelizer is a history and public affairs professor at Princeton University and the editor of "The Presidency of Barack Obama: A First Historical Assessment." He's also the co-host of the "Politics & Polls" podcast. Follow him on Twitter: @julianzelizer. The opinions expressed in this commentary are his own.

(CNN) This past week President Donald Trump went after some of his favorite targets. Within the span of a few days, he lashed out at migrants in Central America who are seeking legal asylum in the US, dismissed his predecessor as "Cheatin' Obama," brought back his false claims about voters committing massive fraud in the 2016 election and went after a few of his most-hated news organizations, including CNN and the Washington Post. "The Washington Post is far more fiction than fact," the president tweeted Sunday morning.

None of this is new. The rhetorical barrage of anger is a prime example of the president's favorite political tactic -- he classic wartime strategy of vilifying, criminalizing and dehumanizing the "enemy."

In times of war, it has been common for presidents to drum up public support for a military operation by rallying the nation against an evil that lurked overseas. Sometimes it hasn't taken much effort by a president to make this case, such as with Adolf Hitler in the early 1940s. Other times, such as with Saddam Hussein in 2002 and 2003, the commander in chief faces a much bigger challenge in trying to prove that an enemy represents a direct threat that requires military action.

This tactic has been central to the President's method of political combat at home. Often using catchy monikers to make his case, President Trump goes all in when he rips apart a target, with the goal of making certain the public can never look at that person or institution the same way again. By the time he is done with them, Trump's hope is that the public won't trust an individual or organization, won't believe anything that they say and will fear them as threats to the republic.

Since showing that he could do this to his Republican primary competitors and then Hillary Clinton, Trump has stuck to this playbook. His vitriol has been intense and he has been willing to go to extreme lengths -- stretching the truth or making things up -- to generate fear and anger.

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