I found an interesting piece in The New York Times that details the differences between Ted Cruz’s ground game in Iowa and Donald Trump’s.

Here are the two ways the approaches are different, and why they matter:

1. Cruz is targeting consistent GOP voters, while Trump is targeting non-traditional GOP caucus goers.

The Cruz campaign has a very sophisticated approach and is tapping into their 1,537 precinct captains (that’s 91 percent of all precincts) to contact a range of voters, but they are focusing primarily on those that have a consistent record of turning out. Their precinct captains are using handwritten notes and personal calls from a carefully scripted set of talking points. They are focusing on getting people to make commitments to show up and vote for Ted to increase the likelihood of them showing up to the polls.

Trump, by contrast, is focusing on the air war — blowing up huge events and rallies, handing out fliers with caucus and voter registration info to anyone that attends, and keeping a major presence on national and local news. Trump is relying on a wave of new voters to show up and vote for him.

If Cruz is a ground invasion, Trump is a napalm strike.

2. Cruz is relying on direct voter contact, while Trump is relying on media and rallies. 

A Monmouth poll last week showed that 25 percent of likely GOP caucus goers said they had been contacted by the Cruz campaign, while only 13 percent (half of Cruz’s number) had been contacted by the Trump campaign. Why does this matter? Check it out:

Mr. Cruz’s supporters in offices here and in northwestern Iowa were making more than 15,000 calls a day, with a refined list of exactly which voters they have identified as up for grabs. Mr. Roe said at a Bloomberg Politics breakfast on Friday that there were 9,131 Iowans deciding between Mr. Cruz and Mr. Trump, 3,185 choosing between Mr. Cruz and Ben Carson and 2,807 who were down to Mr. Cruz or Senator Marco Rubio of Florida.

If those voters make up their minds based on how much contact they have had with the campaigns, it could be enough for Mr. Cruz, the junior senator from Texas, to pull out a win.

Cruz is still the underdog, but he’s now set the expectations to the point where if he wins Iowa tonight, his momentum will be very hard to stop going into South Carolina.

Does a ground game still matter in Iowa? We will find out tonight.

Terry Schilling is the executive director of American Principles Project.