Showdown over Supreme Court nominee Merrick Garland, Republican insiders try to "Stop Trump" 

President Obama nominated Federal Appeals Court Judge Merrick Garland to fill the Supreme Court seat left vacant after the death of Antonin Scalia last month, but Senate Republicans have vowed not to hold hearings or vote on his nomination. NBC's Pete Williams examines Garland's background and the potential ideological shift on the Court. Plus, The New York Times' Peter Baker reports on the fight brewing on Capitol Hill. The Washington Post's Karen Tumulty reports on the state of the 2016 race for the White House as Republicans Ted Cruz and John Kasich continue to battle Donald Trump for the GOP nomination, and the Republican Party prepares for a contested convention.