But as this week’s Democratic debates in Detroit illustrated, many of those initial co-sponsors, fearful of blowback from voters — particularly those who have satisfactory private health insurance they’re reluctant to give up for something unknown, as they would have to under Sanders’s plan — have begun backing away.

Sanders’s Medicare For All would expand to all American residents the government-run health insurance program that’s covered senior citizens and certain other people for over 50 years. But as the costs and disruptions of the plan have come into focus, Medicare for All has emerged as the major fault line in the Democratic presidential primary…

A PBS NewsHour/Marist poll of U.S. adults conducted July 15-17 highlighted the Democrats’ dilemma. It found that while 70% of respondents favor a Medicare for All option, only 41% support doing away with private health insurance. A recent tracking poll from the Kaiser Family Foundation showed overall favorability for a Medicare for All system dropped to 51% in July from 56% in April. It also found that more Democrats, 55%, prefer to expand coverage by bolstering the Affordable Care Act than the 39% who believe in replacing Obamacare with a Medicare for All system.