Sen. Jacky Rosen (D-Nevada) is making a record-breaking ad buy as she gears up for a closely-watched Nevada Senate race, Axios has learned.

Why it matters: The $14 million fall ad buy from Rosen comes after Cook Political Report moved the race, which could determine control of the chamber, to a toss-up on Wednesday.

• The ad buy will run from late July through the November election. It is the largest in Nevada history, according to the Rosen campaign.
• It includes TV and radio hits running in the Las Vegas and Reno markets.

The big picture: The Rosen campaign is placing the eye-popping advertising reservation as a contentious primary plays out on the Republican side.

• Republican Jeff Gunter, a former U.S. ambassador to Iceland under the Trump administration, has painted himself as the MAGA candidate in the race.
• But Republican Sam Brown, an Army veteran, has picked up the support of the National Republican Senatorial Committee, giving him institutional party backing.

Between the lines: President Biden won Nevada by two points in 2020, but Democrats are increasingly anxious about the 2024 contests in the state.

• Sen. Catherine Cortez Masto (D-Nevada) defeated Republican Adam Laxalt by less than a percentage point in the 2022 midterms.
• Former President Trump is leading Biden in polls of the state so far this cycle.

What they're saying: "While her extreme Republican opponents are busy trying to out-MAGA each other, Jacky Rosen is reaching Nevada voters for the general election and sharing her record as one of the most bipartisan and effective Senators," Stewart Boss, Rosen's campaign manager, said in a statement.