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First Read: Are Rubio and Sanders playing to win?

After Trump's third-straight victory last night and as Clinton is set up for a big triumph in South Carolina, what's next for their main rivals?

Democratic presidential candidate Sen. Bernie Sanders (D-VT) waves as he is introduced during a Future to Believe rally at the Bon Secours Wellness Arena on Feb. 21, 2016 in Greenville, S.C. (Photo by Joe Raedle/Getty)
Democratic presidential candidate Sen. Bernie Sanders (D-VT) waves as he is introduced during a Future to Believe rally at the Bon Secours Wellness Arena on Feb. 21, 2016 in Greenville, S.C.Getty Images

Chuck Todd

Chuck Todd is NBC News' chief political analyst and the former moderator of "Meet The Press."

Carrie Dann

Mark Murray