Lawyers for the states opposing President Trump’s plan say it would violate the Constitution. The Census Bureau says it doesn’t yet know how many undocumented people are in the U.S. and can’t say when they will know, so a majority of the justices seemed reluctant to decide the issue now. » Subscribe to NBC News: http://nbcnews.to/SubscribeToNBC » Watch more NBC video: http://bit.ly/MoreNBCNews NBC News is a leading source of global news and information. Here you will find clips from NBC Nightly News, Meet The Press, and original digital videos. Subscribe to our channel for news stories, technology, politics, health, entertainment, science, business, and exclusive NBC investigations. Connect with NBC News Online! Visit NBCNews.Com: http://nbcnews.to/ReadNBC Find NBC News on Facebook: http://nbcnews.to/LikeNBC Follow NBC News on Twitter: http://nbcnews.to/FollowNBC Follow NBC News on Instagram: http://nbcnews.to/InstaNBC #SupremeCourt #Trump #NBCNews Supreme Court Hears Arguments In Trump’s Plan To Exclude Undocumented Immigrants From Census