Nevada is shaping up to be one of the marquee Senate races this cycle, and we believe that first-term Sen. Catherine Cortez Masto is the most endangered Democratic incumbent — a belief backed up by several Democratic and Republican strategists we've talked to over the past few months. Ahead of the June 14 primary, former Attorney General Adam Laxalt is the favorite to secure the GOP nomination, though he faces an insurgent bid from wounded Army veteran Sam Brown.

Cortez Masto succeeded former Senate Majority Leader Harry Reid in 2016 when the Nevadan retired and subsequently endorsed the former attorney general to take his seat. She beat Republican Rep. Joe Heck by a 47.1%-44.7% margin, becoming the first Latina elected to the Senate. But her total narrowly trailed the 46.8 percent Hillary Clinton netted in the presidential race in Nevada.

Six years later, there are several reasons why Cortez Masto, in particular, is the most vulnerable. Nevada is a uniquely transient state: half of those on the state's voter rolls have registered since 2016, when Cortez Masto was

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