Democratic presidential candidates Bernie Sanders and Hillary Clinton participate in the PBS NewsHour Democratic debate in Milwaukee, Wis., on Feb. 11, 2016. There were only six debates planned for the Democratic primary — which caused some to accuse Democratic National Committee Chairwoman Debbie Wasserman Schultz of trying to rig the election for Clinton. In February, the Clinton and Sanders campaigns agreed to extend the Democratic debate schedule by four more debates. Three were held, but Clinton turned down a fourth debate, which would have been held before the California primary.

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