IOWA CAUCUSESPhotos: Democratic presidential candidate Robert F. Kennedy at the Des Moines Register's SoapboxLily SmithDes Moines RegisterDemocratic presidential candidate Robert F. Kennedy speaks at the Des Moines Register Political Soapbox during day three of the Iowa State Fair on Saturday, August 12, 2023 in Des Moines.Lily Smith/The RegisterDemocratic presidential candidate Robert F. Kennedy speaks at the Des Moines Register Political Soapbox during day three of the Iowa State Fair on Saturday, August 12, 2023 in Des Moines.Lily Smith/The RegisterDemocratic presidential candidate Robert F. Kennedy speaks at the Des Moines Register Political Soapbox during day three of the Iowa State Fair on Saturday, August 12, 2023 in Des Moines.Lily Smith/The RegisterDemocratic presidential candidate Robert F. Kennedy signs autographs before his appearance at the Des Moines Register Political Soapbox during day three of the Iowa State Fair on Saturday, August 12, 2023 in Des Moines.Lily Smith/The RegisterDemocratic presidential candidate Robert F. Kennedy speaks at the Des Moines Register Political Soapbox during day three of the Iowa State Fair on Saturday, August 12, 2023 in Des Moines.Lily Smith/The RegisterDemocratic presidential candidate Robert F. Kennedy speaks at the Des Moines Register Political Soapbox during day three of the Iowa State Fair on Saturday, August 12, 2023 in Des Moines.Lily Smith/The RegisterDemocratic presidential candidate Robert F. Kennedy speaks at the Des Moines Register Political Soapbox during day three of the Iowa State Fair on Saturday, August 12, 2023 in Des Moines.Lily Smith/The Register