WASHINGTON — When Representative Jamie Raskin enters a Capitol Hill hearing room on Tuesday to lay out what the House committee investigating the Jan. 6 attack has uncovered about the role of domestic extremists in the riot, it will be his latest — and potentially most important — step in a five-year effort to crush a dangerous movement.
Long before the Jan. 6, 2021, assault, Mr. Raskin, Democrat of Maryland, had thrown himself into stamping out the rise of white nationalism and domestic extremism in America. He trained his focus on the issue after the deadly Unite the Right rally in Charlottesville, Va., five years ago. Since then, he has held teach-ins, led a multipart House investigation that exposed the lackluster federal effort to confront the threat, released intelligence assessments indicating that white supremacists have infiltrated law enforcement and strategized about ways to crack down on paramilitary groups.
Now, with millions of Americans expected to tune in, Mr. Raskin — along with Representative Stephanie Murphy, Democrat of Florida — is set to take a leading role in a hearing that promises to dig deeply into how far-right groups helped to orchestrate and carry out the Jan. 6 assault at the Capitol — and how they were brought together, incited and empowered by President Donald J. Trump.