Republican presidential campaigns have poured an unprecedented $124 million-plus into video and TV advertising in Iowa, according to estimates from AdImpact.

Why it matters: The Iowa caucuses not only kick off the 2024 presidential primary, but they set the tone for the remainder of the campaign.

• "Everything is nationalized now," said Matt Gorman, former senior adviser for Tim Scott's campaign.
• "How you do in Iowa forms a narrative that leads you into New Hampshire. Thinking you can generate momentum out of thin air, with just a week between the two, is a fallacy."

Details: As of last Friday, 46% of all Republican presidential primary video ad spending ($270 million) had been used to try to pursue Iowa voters, according to AdImpact, an advertising data firm.

• In the two weeks leading up to the caucuses, groups supporting former South Carolina Gov. Nikki Haley have spent $7.8 million on ads, followed by ads for Florida Gov. Ron DeSantis ($6.1 million), pro-Trump ads ($3.5 million) and ads supporting businessman Vivek Ramaswamy ($127,000).
• Even more money has been spent on fundraising and get-out-the-vote ads targeted to Iowans on platforms like Google and Facebook, according to their respective online ad libraries.
• Ramaswamy's campaign suspended all TV ads weeks before the caucuses in favor of cheaper marketing tactics.

Yes, but: While ad spending can help build name recognition, Iowa caucusgoers have come to expect in-person courtship above all else.

• "History has shown that ads do not win caucuses," said Tim Lim, president of Lim Consulting and a Democratic consultant.
• "It looks like Trump's caucus to lose and the biggest spender won't be the victor in Iowa on Monday."

The big picture: The advertising dollars spent on U.S. elections and advocacy issues will grow to a record $16 billion this year, up 31.2% compared to the last presidential election in 2020, Axios reported in December.

Go deeper: Campaign cash floods 2024 swing states