Florida Gov. Ron DeSantis is on track to finish in second in Monday's Iowa caucuses in a crucial performance for his presidential campaign, AP projects.

Why it matters: DeSantis campaigned more aggressively in Iowa than he has in most other early primary states.

• He staved off a challenge from former United Nations Ambassador Nikki Haley for second, despite her late surge of momentum.
• Former President Trump won decisively on Monday, the Associated Press projected just 30 minutes after the caucuses began.

The big picture: The stakes were high for DeSantis heading into Iowa after he poured a huge amount of time and money into campaigning across the state. (He said he visited all 99 counties across Iowa).

• He also won the endorsement from popular Iowa Gov. Kim Reynolds and the backing of influential evangelical leader Bob Vander Plaats.
• But DeSantis battled with Trump to win the support of evangelical and conservative voters.

Between the lines: Extreme weather conditions in Iowa in the final days before the caucuses raised questions over turnout.

• Campaigns were forced to cancel events as huge snow totals and bitter cold enveloped the state.

Zoom in: Trump held a commanding lead in polls for months leading up to the caucuses, making the contest largely a fight for second between DeSantis and Haley.

• Haley and DeSantis repeatedly took swipes at each other on the campaign trail and they both hit each other over their records during the final Republican primary debate before the caucuses.
• While DeSantis campaigned more aggressively in Iowa than Haley did, she earned financial and grassroots support from GOP donors who saw her as the best alternative to Trump.

What to watch: DeSantis now faces a tough path forward in New Hampshire, where Haley appears to have a solid hold on the second-place positioning and is seeking to catch Trump.

Go deeper: DeSantis escalates attacks on Trump ahead of Iowa