Why it matters: Biden aides believed they were winning when the race was about the coronavirus pandemic. Now they plan to use the Supreme Court opening as a raucous new field for a health care fight, returning to a theme that gave Democrats big midterm wins in 2018.

Here’s the case Biden will make: The new justice could have a deciding vote on protections for pre-existing conditions.

Biden said in Philadelphia on Sunday: “There is so much at stake — the right to health care, clean air and water, and equal pay for equal work. The rights of voters, immigrants, women and workers.”

The Biden campaign will coordinate closely with House and Senate Democratic leaders on how to link the Supreme Court fight to Trump’s coronavirus response.