Republican presidential candidates have returned to the campaign trail following Tuesday’s Republican presidential debate. In Arizona, Maricopa County Sheriff Joe Arpaio, whose office the U.S. Justice Department has said holds a “systematic disregard for basic constitutional protections,” introduced candidate Donald Trump at a rally by reminding the audience that the two of them are both prominent “birthers” who question the validity of President Obama’s U.S. birth certificate.

Sheriff Joe Arpaio: “We have something in common—the birth certificate investigation, which is still going on; illegal immigration. And one more thing we share: birthday.”

Donald Trump has been one of the leaders of the birther movement. In 2011, he claimed to have sent investigators to Hawaii.