AOC on Biden's primary wins: Tonight's a tough night

Rep. Alexandria Ocasio-Cortez told supporters as former Vice President Joe Biden was projected big wins in Tuesday's primaries it had been a "tough night" for her chosen Democratic presidential candidate, Sen. Bernie Sanders.

Why it matters: "There's no sugar-coating it. Tonight's a tough night. Tonight's a tough night electorally ... [but] never, ever, ever let your heart turn black," Ocasio-Cortez said during an Instagram live broadcast. While Sanders has yet to comment on Biden being projected to win the Michigan, Mississippi and Missouri presidential primaries, Ocasio-Cortez's comments carry significant weight as one of the Vermont senator's highest-profile supporters.

Go deeper: Rep. Clyburn: DNC should "step in" for Biden after Tuesday's contests