The biggest decision facing Elizabeth Warren is not whether to end her campaign, but rather whether to endorse Joe Biden, Bernie Sanders or neither.

“That’s the only real choice facing her now,” a Warren adviser tells CNN.

Warren is closer to Sanders — policy speaking — but those ties are strained. Some advisers believe her best path is to be considered as a vice president to Biden.

As CNN has reported, Warren is assessing her path forward. Her plan was to emerge as the alternative to Biden and Sanders — with her sights set on appearing on the debate stage in Phoenix later this month.

Those hopes are now almost certainly dashed. But Warren has to make the decision for herself: When to drop out and who — or whether — to endorse.