The Postal Service has urged state election officials to pay first class for mail ballots, which Senate Democratic Leader Chuck Schumer says could nearly triple the cost.

Why it matters: Senate Democrats claim that "it has been the practice of USPS to treat all election mail as First Class mail regardless of the paid class of service."

USPS public relations manager Dave Partenheimer told me by email: "For years, the Postal Service has emphasized to the election community that delivery times are based on the class of service paid for by the mailer."

• Partenheimer's statement says the lower rate "will result in slower delivery times and will increase the risk that voters will not receive their ballots in time to return them by mail."

Go deeper:Read a letter from Senate Democrats to Postmaster General Louis DeJoy