(CNN) First things first: The theme song of the week is The Days and Nights of Molly Dodd.

: A new Kaiser Family Foundation poll finds that when it comes to expanding coverage and lowering health care costs 55% of Democrats and Democratic leaning independents prefer to vote for a candidate who does so by building on the Affordable Care Act. Only 40% want do so by voting for voting for a candidate who replaces the ACA with Medicare for All.

This poll is consistent with previous Kaiser polls on the subject in finding Democrats wanting to vote for someone who builds on the ACA.

What's the point: Another Democratic presidential debate was defined by whether it's best to improve health care coverage through Medicare for All with minimal private insurance or having private insurance with a government run health care option. Vermont Sen. Bernie Sanders and Massachusetts Sen. Elizabeth Warren argued the former, while some others, most prominently former Vice President Joe Biden, argued the latter.

Polls like the one I just cited indicate that the candidates who favor a public option hold the majority opinion within the Democratic Party.

Our CNN poll from late June directly posed the question to potential Democratic primary voters. We asked whether there should be a national health care plan and whether it should replace private insurance. The plurality, 49%, said there should be a government health care plan but it shouldn't eliminate private insurance. Just 30% said there should be a national health care plan and it should eliminate private insurance. A mere 13% didn't want a government run health care plan.

The polling shouldn't be too surprising when you look at how Democrats feel out their own health insurance: they like it.

According to Gallup polling from late last year, 82% of Democrats said the quality of health care they received was either good or excellent. A large majority, 71%, believed their health care coverage was either good or excellent. Even when it comes to health care costs, 61% of Democrats said were satisfied with what they paid in health care.

On Thursday, Warren argued that , despite these numbers, she has "actually never met anybody who likes their health insurance company."

It turns out that Kaiser posed this question to Americans back in 2013 "Do you have a generally favorable or generally unfavorable opinion of your own health insurance company?"

In that poll, 72% of Democrats they had a favorable view of their health insurance company. That's triple the 24% who said they had an unfavorable view.

This polling is probably the reason that most of the Democrats on the Thursday debate stage don't want to mostly eliminate private insurance companies. It might also explain why Biden continues to lead the Democratic race. He's closer to the median voter on the marquee issue this primary season than either his two leading competitors Sanders or Warren.

If Sanders or Warren win the nomination, it will be in spite of their health care positions, not because of them.

Even if Sanders or Warren do become their party's nominee, it should be noted their health care stances are likely to be even more harmful in the general election. While 54% of all voters want a national health insurance option in CNN polling, just 19% believe that should come by eliminating private health insurance. When not offered the public option and asked directly by Marist College if it was a good idea to replace private insurance completely with a national health insurance plan, 40% of voters said it was a good idea and 55% said it was a bad idea.

Moreover, 58% of all Americans told Gallup last year they were satisfied with their health care costs and clear majorities answered good or excellent on the quality of their health care (80%) and coverage (69%). And similarly to Democrats, 74% of all Americans told Kaiser in 2013 that they had a favorable view of their own health insurance company.

Perhaps the best hope for Sanders and Warren is to not make health care personal. Americans may like their own insurance and their own insurance company, but just 20% are satisfied with the total cost of health care in America. A minority (43%) have a favorable view of health insurance companies at large.

But when you propose eliminating private insurance, it's pretty hard not to make it personal to the many voters who rely on it.