Donald Trump has dropped by Iowa occasionally. Nikki Haley has been there more often, and Ron DeSantis and Vivek Ramaswamy have been blanketing the state in advance of the Jan. 15 GOP caucuses.

Why it matters: Their differing approaches to the first contest of the 2024 primary season — the intensity of their campaigning, their number of public events and the communities they've targeted — shed light on how each candidate views Iowa, and their strategies for moving forward.

Driving the news: Trump, with a big lead in the polls, has stuck mostly with big rallies in urban centers and help from surrogates such as former Housing and Urban Development Secretary Ben Carson and South Dakota Gov. Kristi Noem.

• From Jan. 1, 2023, through Thursday, Trump had held 24 events in Iowa, far fewer than his challengers. He stepped up his pace this weekend, when he began a series of appearances that will continue through next week.
• His relaxed approach over the past year has reflected his confidence as the frontrunner — and his court schedule, as he faces felony charges in four jurisdictions.
• Now, the former presiden's his rush to close the deal with conservative voters in Iowa is a signal that he's hoping to crush DeSantis' hopes from the start — and try to stem Haley's recent rise. Trump's increasing focus on Haley was evident in his speech in Sioux City on Friday, when he cast his former UN ambassador as weak on border security.

Zoom in: An analysis of the other GOP candidates' travel and event schedules in Iowa, gleaned from data collected by the Des Moines Register, reveals how they've tried to carve into Trump's lead — or do well enough to survive until the next contest, in New Hampshire.

• DeSantis claims to have visited all 99 Iowa counties, and appears to be using much of the playbook that Sen. Ted Cruz (R-Texas) used in winning the Iowa caucuses in 2016.
• The Florida governor has been guided by former Cruz strategists such as Jeff Roe and David Polyansky, and he's campaigned aggressively in many of the farm counties in Iowa that Cruz won.
• DeSantis' path in Iowa has been complicated by Trump's popularity among evangelicals, who make up a large chunk of the GOP base in Iowa, were a key part of Cruz's coalition, and now are key to DeSantis' success.
• But many evangelicals are siding with Trump, rewarding him for his appointment of conservative judges who overturned the constitutional right to abortion.

Haley has emphasized campaign stops in Iowa's voter-dense suburbs — including Scott, Polk and Story counties, which Sen. Marco Rubio (R-Fla.) won in the 2016 caucuses, and Blackhawk County, which Trump won.

• She's held 51 events in Iowa during the past year, more than double Trump's number, but far fewer than DeSantis (99) and Ramaswamy (239).
• Haley has seemed especially focused on the Jan. 23 primary in New Hampshire, where she's polling within 10 points of Trump.
• But Haley, backed by big donations from Republican donors pushing for an alternative to Trump, is spending heavily in Iowa.
• Her campaign and a pro-Haley super PAC have booked a whopping $4.6 million in ads — far more than her opponents — in the two weeks before Jan 15. Iowans who tuned in to watch the Iowa Hawkeyes play in the Cheez-it Citrus Bowl on New Year's Day saw a lot of Haley on their screens.

Ramaswamy has been the most active candidate in Iowa, holding as many as 10 events a day. Like DeSantis, Ramaswamy says he's campaigned in every Iowa county.

• But polls suggest that Ramaswamy — an entrepreneur who last week gave his campaign a boost by selling $33 million in stock in a biotech company he founded — hasn't gotten a lot of bang for his buck.

Between the lines: The Register notes that its candidate tracker includes only scheduled public events, and not the type of small informal gatherings such as when a candidate stops at a diner.

Zoom out: While Trump is widely expected to win the Iowa caucuses, the GOP campaigns and their boosters will be paying particular attention to the margins of victory in Iowa, and then New Hampshire.

• That's because in the early days of primary season, momentum — and meeting expectations — can be everything.

What they're saying: Iowa's caucuses are "all about expectations. Expectations are high for Haley and low for DeSantis," said Justin Sayfie, a former spokesperson for Jeb Bush, the ex-Florida governor.

• "Iowans' support cannot be bought, and success in an Iowa caucus requires both outworking and out-organizing the competition," Polyansky told Axios. "That's where Ron DeSantis is wholly focused."

What's next: Fox News will host a town hall with Trump in Des Moines on Jan. 10, airing at the same time as CNN's GOP primary debate, between DeSantis and Haley.