Officer William Porter, one of six Baltimore city police officers charged in the death of Freddie Gray, arrives to Maryland Court of Appeals, Thursday, March 3, 2016, in Annapolis, Md. Maryland's highest court will hear arguments Thursday on whether Porter can be compelled to testify against his colleagues after his trial ended in a hung jury in November. (AP Photo/Jose Luis Magana)
Officer William Porter must testify against some of the other officers charged with Gray's death
READ MOREVIDEO: John Oliver rips into presidential candidates
READ MOREVideo: Marco Rubio won Puerto Rico but is trailing in delegates
READ MOREVideo:Candidates take aim at each other's records on Wall Street, Trade, auto bailout
READ MOREIn this March 1, 2016, photo, Republican presidential candidate Donald Trump speaks on Super Tuesday primary election night at the White and Gold Ballroom at The Mar-A-Lago Club in Palm Beach, Fla. The possibility of Trump as Republican nominee _ and perhaps president _ is suddenly very real for the GOP in Congress. After months of denial that the billionaire businessman could swipe the nomination from more establishment candidates, senators faced reality on Wednesday. (AP Photo/Andrew Harnik)
Romney says a safe future is 'greatly diminished' with Trump
READ MOREDemocratic presidential candidate Hillary Clinton reacts to supporters as she arrives to address supporters at her Super Tuesday election night rally in Miami, Tuesday, March 1, 2016. (AP Photo/Gerald Herbert)
After several Super Tuesday wins for Donald Trump, an unrelenting division has become the biggest crisis for the GOP in decades
READ MORETrump says he opposed Iraq invasion: He didn't. And other memory lapses...
READ MOREVIDEO: $2 million campaign but Bernie Sanders failed to win over Black voters
READ MOREWatch our video showing who will the election promises on immigration affect most
READ MOREGov Kate Brown and Gov Jerry Brown are in; Gov Jay Inslee? Out.
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