Since 1988 when frontloading a significant number of states on a single day became popularized in the GOP primary, it has been decisive in determining the nominee.

The first Republican primary debate, in Milwaukee on Wednesday, will give many Americans the first chance to hear from the GOP presidential candidates, but the party's frontrunner won't be there.

President Biden meanwhile has seen his approval rating stabilize and is well liked among Democrats, though he faces challenges with independents and younger voters.