Throwing in with Republicans seems like a bridge too far. It’s not as though Ms. Sinema is an actual conservative. But easing over into the independent column could be a gentler, less disruptive transition. She could still caucus with the Democrats, much like her independent colleagues Angus King and Bernie Sanders.

A split still wouldn’t be easy. The logistics would be a nightmare. And while open relationships often sound great in theory, they can be excruciating to navigate. But Ms. Sinema has a better shot than most at not just surviving such a shift, but becoming a truly independent force to be reckoned with — maybe even a power broker for years to come.

This is what many of her critics miss. They see her as a chameleon, unprincipled and narcissistic, an intellectual lightweight without any steady, guiding tenets. But she does have a guiding principle. She holds fast to an abhorrence of the toxicity and dysfunction of the hyper-polarized political system, brandishing a potent combination of disgust, frustration and moderation that could, come to think of it, put her in sync with a big slice of Americans