Democratic candidates Hillary Clinton, Bernie Sanders and Martin O'Malley will face off in Iowa at 9 p.m. ET.
The Democratic front-runner has locked up support from 359 superdelegates.
In September, liberal firebrand Sanders had taken the lead in the early primary states of Iowa and New Hampshire.
Police say body found stuffed behind false wall in apartment is likely that of missing woman.
The Democratic presidential candidate's latest policy proposal is a shot at rival Bernie Sanders.
"We have a problem in this country. It's called Muslims," the questioner said.
Republicans are offering a choice between sanctuary cities and thousand mile anti-rapist walls.
Vermont senator edges ahead in early 2016 presidential primary states.
Survey says 41 percent of Democratic voters would back Sanders with Biden in race.
Owen Labrie, 19, has pleaded not guilty to charges of sexually assaulting the girl at St. Paul's School in Concord in May 2014.
In fact, a handful of other contests may determine the Republican presidential nominee.
Prosecutors say Owen Labrie took a 15-year-old girl to the roof of a building at St. Paul's School in New Hampshire and sexually assaulting her.
Sanders bests Clinton 44 percent to 37 percent in the bellwether state, a poll from Franklin Pierce University and the Boston Herald reveals.
Will the rightward tilt of the GOP prevent it from winning the White House and governing effectively?
The Republican presidential candidate told a New Hampshire newspaper that "people need to work longer hours," drawing a Twitter jab from Hillary Clinton
"Emailgate" is causing Hillary Clinton to lose support in the swing state.
The Granite State is a microcosm on the eve of midterm elections
"I'm going to fight this with every fiber in my body," Perry told business leaders
Ibrahim and her family are starting their new life in Manchester, New Hampshire