Since he retook office, President Donald Trump has sought to discourage social media companies from taking down posts they deem hateful or misleading. Now his administration is using immigration policy to ratchet up that pressure. The State Department this week issued additional guidance that could deny visas to workers involved in online content moderation, which Republicans argue is a threat to Americans' free speech. The move is part of an "enhanced vetting" process for H-1B visas widely used by Silicon Valley firms to bring skilled tech workers into the country.