MARSHALLTOWN, Iowa (AP) — New Jersey Sen. Cory Booker says having been a big city mayor distinguishes him from his rivals for the 2020 Democratic nomination. Asked during a campaign stop in Marshalltown what separates him from fellow Sens. Kamala Harris and Elizabeth Warren, he said it’s that he’s “run something.”

Booker was mayor of Newark from 2006 to 2013 before being elected to the U.S. Senate. He says the experience running a troubled urban center during a financial crisis would help him as president.

Harris, a senator from California, was attorney general of her state for eight years before her 2016 election to the Senate. Warren, a Massachusetts senator, was a law school professor and a leading advocate for the creation of the Consumer Financial Protection Bureau before entering the Senate.