Big wins for front-runners Clinton, Trump

8:21 AM ET Wed, 16 March 2016

Republican presidential candidate Marco Rubio is exiting the race for president, and Donald Trump took Florida for the GOP, and Hillary Clinton for the Democrats. CNBC's John Harwood reflects on a night of U.S. primaries, where he says Clinton took a big step toward the Democratic nomination. Also, President Obama is set to announce his U.S. Supreme Court nomination Wednesday afternoon.