New polling shows President Trump trailing four of the Democratic presidential contenders. Former Vice President Joe Biden leads Mr. Trump by nine points. Senators Bernie Sanders, Elizabeth Warren, and Kamala Harris are also ahead. Ed O'Keefe reports. Watch "CBS This Morning" HERE: http://bit.ly/1T88yAR Download the CBS News app on iOS HERE: https://apple.co/1tRNnUy Download the CBS News app on Android HERE: https://bit.ly/1IcphuX Like "CBS This Morning" on Facebook HERE: http://on.fb.me/1LhtdvI Follow "CBS This Morning" on Twitter HERE: http://bit.ly/1Xj5W3p Follow "CBS This Morning" on Instagram HERE: http://bit.ly/1Q7NGnY Get new episodes of shows you love across devices the next day, stream local news live, and watch full seasons of CBS fan favorites anytime, anywhere with CBS All Access. Try it free! http://bit.ly/1OQA29B Each weekday morning, "CBS This Morning" co-hosts Gayle King, Anthony Mason and Tony Dokoupil deliver two hours of original reporting, breaking news and top-level newsmaker interviews in an engaging and informative format that challenges the norm in network morning news programs. The broadcast has earned a prestigious Peabody Award, a Polk Award, four News & Documentary Emmys, three Daytime Emmys and the 2017 Edward R. Murrow Award for Best Newscast. The broadcast was also honored with an Alfred I. duPont-Columbia Award as part of CBS News division-wide coverage of the shootings at Sandy Hook Elementary School in Newtown, Connecticut. Check local listings for "CBS This Morning" broadcast times.