The Democratic National Committee has increased its requirements for participating in the March 15 debate in Arizona, hosted by CNN and Univision, the next Democratic debate of the primary season. The new requirements mean Tulsi Gabbard will not be on the stage.

Under the new requirements, candidates must have at least 20% of the total number of pledged delegates, a requirement only Joe Biden and Bernie Sanders have met. The previous rules only required candidates to secure one delegate, which Gabbard did in American Samoa.

Gabbard has not yet addressed the new requirements.

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Since the South Carolina primary on February 29, Tom Steyer, Amy Klobuchar, Pete Buttigieg and Elizabeth Warren have all dropped out, effectively making it a two-way race between Sanders and Biden. Klobuchar and Buttigieg both endorsed Biden, as did former presidential candidate Beto O'Rourke.

The winnowing of the field to effectively Sanders and Biden has given the Democratic Party a clear contrast in vision moving forward — a return to the policies of former President Obama, or a significant expansion of the responsibility of a federal government, as designed by a democratic socialist. Since Super Tuesday, Sanders and Biden have ramped up their attacks on each other, with Biden calling Sanders' plans unrealistic and costly, and Sanders suggesting Biden is beholden to corporate interests. Biden currently holds an edge in the delegate count.