Elizabeth Warren, speaking in the first Democratic presidential debate of the 2020 cycle, declared "I'm with Bernie" on a plan to end private insurance for about 180 million Americans, and migrate all Americans to a single government-run plan.

Though the Massachusetts senator had already co-sponsored Sen. Bernie Sanders' plan to socialize the health insurance system under the brand "Medicare for all," she had been equivocating on the campaign trail, raising questions about whether she might in reality support a plan that would create a new government-run plan while stopping short of eliminating private insurance.

But on Wednesday's debate stage, she left no doubt.

First, she raised her hand when asked by moderators whether she would support getting rid of private insurance, and also declared, "I'm with Bernie on 'Medicare for all.'"

The Sanders plan would force everybody off of their insurance within four years to a new government-run plan which promises generous coverage with no co-payments, premiums, or deductibles. The only remaining role for private coverage would be to offer narrow coverage on services not paid for by the government plan — which promises to offer a broad array of medical benefits in addition to dental services and optical care.

There are nearly 180 million people with private coverage they purchased on their own or through their employers, and every one of them would lose their plans under the one Warren just endorsed.

Thus, this is an incredibly risky strategy that may prove myopically tailored to her primary battle with Sanders. The truth is people with private coverage are overwhelmingly satisfied with their healthcare, and support for the vague concept of "Medicare for all" turns into significant opposition once people are told it would eliminate private insurance.

Warren seems to be calculating that if she's the Democratic nominee and it becomes her versus President Trump, the benefits of confidently making a consistent populist case against private insurance outweigh the potential risks.

She also may be informed by Sen. Kamala Harris, who has stumbled on the issue by saying she supports "Medicare for all" only to flip around on whether she would support eliminating private insurance — putting herself in an incoherent position.