This is the editor’s letter in the current issue of The Week magazine.

"Public sentiment is everything," Abraham Lincoln once said. "With public sentiment, nothing can fail. Without it, nothing can succeed." It's endlessly surprising how often this foundational principle of democratic politics eludes activists and elected officials in both parties' ideological extremes. Sen. Elizabeth Warren has bet her surging presidential campaign on Medicare-for-all, fired by the conviction that 150 million Americans should be happy to trade in private health coverage for a government-run system they've never experienced. But an NBC News/Wall Street Journal poll recently found just 41 percent supported a single-payer system that eliminates private insurance, with 56 percent opposed — a consistent finding in public surveys.

Opposition to Medicare-for-all would only grow during a general election campaign, as Republicans target "socialized medicine" with $1 billion in negative advertising. The ads write themselves: long wait times to see doctors, 30 percent cuts in payments to doctors and 40 percent to hospitals (figures straight from ­Bernie Sanders' plan), hospital closures, and rationing. But let's say Warren wins the election anyway. In a sharply divided country, could Dem­o­crats ram legislation through Con­gress that mandates a 65 percent hike in federal spending, $3 trillion in new taxes, and a revolutionary upheaval in an industry affecting the well-­being of every Amer­i­can? Without Re­pub­li­can votes, Dem­o­crats would own the new health-care ­system — and get full blame every time people were unhappy with their care. A traumatic transition period could trigger the Mother of All Backlashes, more punishing than the Tea Party backlash to Obama­Care that cost Dem­­o­­crats both the House and the Sen­ate. Never mind, say the purists who disdain an optional, "Med­i­care for those who want it" plan as too incremental — despite polls showing this alternative has 75 percent support. Who needs public sentiment when you are certain the public is wrong?