Does the U.S. need a domestic terrorism law to fight extremism?

The deadly attack at the U.S. Capitol last week has revived an ongoing debate over whether federal law enforcement should be given more authority to fight homegrown terrorism at the same level the U.S. combats terrorism abroad.

President-elect Joe Biden was one of many lawmakers to refer to the mob of Trump supporters who stormed the Capitol building as “domestic terrorists.” The rioters’ attempt to forcibly stop Congress from certifying Biden’s election victory appears to meet the legal standard for domestic terrorism, which is defined under U.S. law as violent...