The violent insurrection against our nation’s Capitol building this month pulled an ugly truth to the surface, one that’s been hiding in plain sight for decades. White supremacist extremism is widespread, deep-rooted and a major threat to our security. In his inaugural address on Wednesday, President Joe Biden named white supremacy as a danger to our unity and vowed to defeat it. But law enforcement and government agencies have refused to acknowledge the full scope of the problem, especially when it appears within their own ranks. Will the attack earlier this month motivate the new administration to take this threat more seriously? Trymaine Lee sits down with Erroll Southers, a former federal agent and an expert in homegrown extremism at the University of Southern California. Southers lays out how white supremacist extremism was fostered over decades in this country, and the steps President Biden can take to begin to address the crisis.  Further Reading: Biden sworn in as president, calls on Americans to 'end this uncivil war' of political divisionThe Trump-fueled riot shocked America. To some, it was a long time coming.