Sinema’s vulnerabilities are more complex.

At a time when she’s winning over Republicans and independents back home, her support for the partisan legislation handed a future GOP challenger a ready-made attack line: She’s more interested in protecting Wall Street than Main Street.

At the same time, unlike Manchin, Sinema also has to worry about the possibility of a primary challenge from her left. Arizona Rep. Ruben Gallego is already teasing a possible primary challenge against the maverick Democrat in 2024.

Between the lines: Sinema was concerned that penalizing private equity firms would adversely affect the small businesses they support — an issue that every other Senate Democrat facing a tough race in 2022 also agreed with. And she also used her leverage to guarantee additional funding for drought resilience, which is a major issue in arid Arizona.