Trump has forgotten his oath of office. History will not remember him kindly | Corey Brettschneider

When faced with a crisis, presidents can inflame divisions or unify the nation. Trump is taking the path of Johnson and not Lincoln

Over the course of American history, presidents have not been judged by whether violence occurred on their watch but by how they responded to it. Each crisis poses the same test: will the person who holds the office use it to steady the republic, or to further polarize it?

The oath of office exists for precisely this moment. It binds the president to something larger than self-interest and party, the constitution and the rule of law. In the wake of rightwing political activist Charlie Kirk's death, Donald Trump has forsaken this oath, instead choosing to wield his immense power to further divide an already polarized nation, not unite it. History will not soon forget this grave act of political opportunism.

Corey Brettschneider is a professor of political science at Brown University. He co-hosts the podcast The Oath and the Office, and is the author of The Presidents and the People: Five Leaders Who Threatened Democracy and the Citizens Who Fought to Defend It