Hillary Clinton's early attacks on Sen. Bernie Sanders' plan for single-payer health care were at best convoluted and at worst simply dishonest. In earlier stages of the campaign, she seemed to suggest that the Vermont senator's desire to "dismantle" America's current suite of public health care programs and replace them with a system of universal government insurance would somehow give Republicans permission to roll back Medicare, Medicaid, and Obamacare. She also attacked Sanders for wanting to raise taxes on the middle class without mentioning that those taxes would, theoretically, just be replacing their health premiums. For whatever reason, she seemed to think Democratic voters couldn't handle the obvious argument that moving to a single-payer system is politically and logistically unrealistic and instead settled for debating in bad faith. Ezra Klein summed it up at Vox with the line, "Hillary Clinton Doesn't Trust You.”
Tonight, at the Democratic debate, she did a better job explaining herself.
Senator Sanders and I share some very big progressive goals. I've been fighting for universal health care for many years and we're now on the path to achieving it. I don't want us to start over again. I think that would be a great mistake to once again plunge our country into a contentious debate about whether we should have and what kind of system we should have for health care. I want to build on the progress we've made. Go from 90-percent coverage to 100-percent coverage. And I don't want to rip away the security that people finally have. Eighteen million people now have health care. Pre-existing conditions are no longer a bar. So we have a difference.
You may not especially like this argument, but it's honest. The wars over Obamacare aren't even over, and Clinton doesn't want to relitigate the fundamental question of how our health care system should be structured. She also doesn't think the government should take away coverage that people already have (likely because, as she learned in the early 1990s, people who have insurance tend to be incredibly protective of it). Instead, she wants to build on the framework that Obamacare put in place and try to expand insurance to those who still don't have it.
Again, you might not agree with all these points. You could argue her own goals aren't even especially achievable, so long as Republicans control the House. But, at least it's a straightforward, sincere argument.