Democratic Sen. Jacky Rosen of Nevada announced a major investment in her reelection bid on Thursday. Her campaign is placing a $14 million ad reservation in Nevada, a battleground state that could not only determine the balance of power in the Senate, but also the presidential election.

Rosen's ad reservation is the largest in the state's history for a Senate race, the campaign says, and will run from late July through Election Day in the Las Vegas and Reno media markets.

On Wednesday, The Cook Political Report, a non-partisan elections tracker, moved the Nevada Senate race from "lean D" to "toss-up," joining three other Senate races in the category: Ohio, Montana, and Arizona. These are top targets for Republicans trying to take the Senate majority in November. 

In an interview on Wednesday with CBS News' Ed O'Keefe, Jessica Taylor, the Senate editor for The Cook Political Report, said the rating shift is indicative of "the state of Nevada, where it has been uniquely affected by the post-Covid economy and then also immigration." 

While Democrats won Nevada by razor-thin margins in 2016 and 2020, the state has been tilting away from Democrats. "When we look at the Biden numbers, this is a state where he's [Biden] consistently trailed Donald Trump, especially in comparison to some of those other swing states," Taylor said.

Unlike Arizona, Ohio, and Montana, Nevada also has a high population turnover. In her analysis, Taylor noted that every election cycle, "a quarter of voters are new" to the Silver State, reducing some of the typical benefits of incumbency.

National Republicans are backing Army veteran Sam Brown in the race for Rosen's seat. But first, he'll have to defeat a handful of candidates in the June primary to advance to the general election.

With roughly seven months until November, Rosen, a freshman Democrat, is already spending big. Earlier this week, Rosen went up with two ads, which are part of a seven-figure campaign. Her campaign declined to reveal a specific figure. One ad, titled "Never Have," is focused on Rosen's willingness to work across the aisle and buck her own party. It's airing simultaneously with a new Spanish-language ad titled "Un Camino Diferente," targeting Latino voters, a key voting bloc in Nevada.

"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," said Stewart Boss, Rosen's campaign manager.

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