According to the latest CBS News Battleground Tracker poll, Senator Ted Cruz has replaced retired neurosurgeon Ben Carson in second place. He is now right behind front-runner Donald Trump in Iowa.
The poll has Donald Trump on top at 31 percent, Ted Cruz second with 21 percent, Ben Carson third at 19 percent, Marco Rubio fourth at 11 percent, Jeb Bush fifth at 5 percent and Carly Fiorina sixth at 4 percent.
The margin of error is plus or minus 6.2 percent.
