Charlie Kirk, the founder of the conservative youth activist organization Turning Point USA, was fatally shot during an event at Utah Valley University on Wednesday. President Donald Trump confirmed Kirk’s death on social media.

In the tragic roll call of violence in American public life, Charlie Kirk’s name joins what has fast become a long list.

The Trump administration has pursued a sweeping crackdown on immigration, including increasing social media vetting and revoking thousands of student visas and aiming to tighten the duration of other...