Politics with Amy Walter: An Unexpected Battle for the Senate Listen Download Embed Share Share this on Facebook (Opens in a new window) Share this on Twitter (Opens in a new window) Share this via Email Princess Walker, of Des Moines, Iowa, fills out her ballot in Iowa's Primary Election at the Polk County Central Senior Center. ( (AP Photo/Charlie Neibergall) ) Produced by GBH, PRX and WNYC Studios