Good campaign slogan! Actually, believe it or not, there hasn't been a mayor of NYC elected on the 'Rat line since Dapper Dave Dinkins in 1989. So maybe it should be, "if you want to return to the bad old days of Dinkins, vote Democrat." But then that would considered "racist" in some circles, I'm afraid.
So change that to “If you want to return to the days before Rudy, vote Democrat.” Leave the negative references implied.