WASHINGTON — The Biden administration is stepping up efforts to combat domestic extremism, increasing funding to prevent attacks, weighing strategies historically used against foreign terrorist groups and more openly warning the public about the threat. Members of the Proud Boys, a far-right group, at a rally in Portland in September. Its leaders are among the most prominent targets of the sprawling investigation into the attack on the Capitol. Members of the Proud Boys, a far-right group, at a rally in Portland in September. Its leaders are among the most prominent targets of the sprawling investigation into the attack on the...