Bill de Blasio, New York City’s Democratic mayor, is being accused of violating conflict of interest laws by wading into the negotiations between Hillary Clinton and Sen. Bernie Sanders (I., Vt.) over a proposed presidential debate in New York.

The Foundation for Accountability and Civic Trust, an ethics watchdog group, says that de Blasio strong-armed Sanders into agreeing to debate on Clinton’s terms by baiting the Vermont senator with permits for a rally in the city later this month. The group argues that de Blasio’s actions advanced the interests of Clinton, whom the mayor endorsed last October.

The Clinton and Sanders campaigns have sparred over scheduling a debate in New York ahead of the primary there later this month. The Clinton campaign proposed a debate in Brooklyn on April 14, a date Sanders initially resisted because he had planned a rally that evening in New York City for which he had already obtained park permits.

“Let’s make ‪@NY1 4/14 BKLYN debate happen,” de Blasio wrote on Twitter Monday morning. “‪@BernieSanders: I’ll help you secure any permit you need to ensure your NYC rally can happen too.”

Later that day, Clinton and Sanders agreed to debate on April 14 in Brooklyn, home to Clinton’s campaign headquarters.

Matthew Whitaker, a former U.S. attorney who serves as executive director for FACT, told the Free Beacon that de Blasio improperly used his city position to push Sanders to agree to a debate on Clinton’s terms.

“It is not only unethical, but an apparent violation of conflict of interest laws for New York City Mayor Bill de Blasio to use the Office of the Mayor to advance the interests of his preferred candidate in the Democratic presidential primary race. Using the Mayor’s office in this manner is a misuse of City resources and implies City endorsement of partisan politics,” Whitaker stated.

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