House managers and the president’s lawyers will have four hours to make their final arguments. Source

The last CBS News Battleground Tracker before the Iowa caucuses has former Vice President Joe Biden and Senator Bernie Sanders tied at the top. “CBS This Morning” co-anchor Tony Dokoupil reports from Des Moines, and CBSN political reporter Caitlin Huey-Burns chats with Radio Iowa news director O. Kay Henderson about the race. Source

In January, three rallies took place within one week showing the glaring polarization of the nation. New York Times national correspondent Sabrina Tavernise joined CBSN to discuss how activists on the left and right put pressure on people in the middle. Source

Companies spent $5.6 million for 30 seconds of air time, but not all of them scored a touchdown, experts say. Source

For five decades, the snowy cornfields of Iowa have yielded a crop of future presidents. And many voters are proud they are the first in the nation to vote in the primary season. Ed O’Keefe reports on how the state became such an important part of the presidential race. Source

Iowa will kick off the 2020 primary election season Monday night. Democrats are in a tight race to be the nominee to face President Trump in November. CBS News chief Washington correspondent Major Garrett and special correspondent Alex Wagner join “CBS This Morning” to discuss the race. Source

In World View, a Syrian Army shelling kills at least four Turkish soldiers, drivers ignore an anti-pollution measure in Milan and U.K. Prime Minister Boris Johnson lays out his vision for a U.K.-EU trade deal. Cindy Pom joined CBSN AM from London with the round up. Source

Democrats in the Hawkeye State have a pretty good track record at predicting their party’s presidential nominee Source

“A moderate candidate’s going to do well,” said Laura Hubka, the chair of the Democratic Party in Howard County. Source

Eleven year old led a chorus of kids covering Gloria Estefan’s “Let’s Get Loud.” Source