A large group of masked members of the white nationalist organization Patriot Front marched through the nation's capital Saturday, striking a discordant note as massive crowds gathered to celebrate the United States' 250th anniversary.Videos and photographs posted to social media showed dozens of men marching in formation near Union Station and other areas of the city. The marchers wore a uniform of navy-blue shirts, khaki pants, tan baseball caps, sunglasses, and white cloth face coverings. They carried American flags, Confederate flags, and various banners.The demonstration took place against the backdrop of sprawling Independence Day festivities commemorating America's semiquincentennial, which drew...