The debate’s first question asks the candidates about health care, which Democrats say is one of the most important issues in their 2020 vote. A Kaiser Family Foundation poll released Thursday found 77 percent of Democrats and Democratic-leaning independents favor adopting a Medicare-for-all national health plan, which has been embraced by Sens. Bernie Sanders (I-Vt.), Elizabeth Warren (D-Mass.) and others. But an even larger 87 percent majority of Democrats support having the government offer a “public option” for health insurance that would compete against private health insurance plans. The public option plan, an approach supported by former vice president Joe Biden, also enjoys wider support among the general public. 

The KFF poll also found that Democrats are overwhelmingly supportive of the 2010 Affordable Care Act and that a 55 percent majority prefers to build on that law rather than replacing the ACA with a Medicare-for-all plan. Relatively few Democrats, 14 percent, said they would vote only for a candidate who wants to replace the ACA with Medicare-for-all.