Republican presidential candidate former President Donald Trump takes the stage at a caucus night party in Des Moines, Iowa, Monday, Jan. 15, 2024. (AP Photo / Andrew Harnik)

About 7 in 10 Iowans who caucused for Donald Trump on Monday night said they have known all along that they would support a man who has remade the Republican Party through his “Make America Great Again” political movement. 

Republican presidential candidate and Florida Gov. Ron DeSantis and his wife Casey, walk in the July 4th parade, July 4, 2023, in Merrimack, N.H. (AP Photo / Reba Saldanha, File)

As the six-month sprint to the Iowa caucuses begins, the sprawling field of Republican presidential candidates is facing growing pressure to prove they can become serious challengers to former President Donald Trump.

White House hopefuls are getting their first test with voters tonight in Iowa, where caucusing is in full swing. Joining us from Des Moines, Iowa to talk about that and more is "Chicago Tonight's" Carol Marin.