I agree that an individual mandate plan is imperfect, and it would be better to enroll everyone through taxes. But there's a reason politicians are so reluctant to advocate such serious changes in financing and organization. Surveys routinely show that 80-some percent of the America people are satisfied with their health care coverage. They want to change the system because they fear for their future in it, but they like what they have right now. And when you like what you have, and what you have is medical care, there's a lot of status quo bias -- it's not something you feel comfortable experimenting with.
It's exactly this attachment to the status quo that was so brutally exploited in 1994, when the various industries shredded the Clinton plan on the grounds that it would take away what people already had. That was, essentially, the attack. And it worked. Because it was true. In order to make health coverage an automatic feature of taxes, you had to construct a whole new structure. But this proposed transformation caused a lot of anxiety; folks feared what they'd end up with in the new system. So the new generation of plans ensures that everyone can keep exactly what they have. That means letting employers continue to offer their current coverage, and keeping large swaths of the current financing structure. In order to let people keep what they already have, you have to retain much of what already exists. From a policy standpoint, that's less than optimal. But from a political standpoint, it appears necessary.
The individual mandate, imperfect though it may be, is an attempt to paste universality atop a system not easily given to it. It's about the best you can do. That's why it's so important that these plans set up, and quietly advantage, federally regulated menus of public and private insurance options which both businesses and individuals can buy into. The hope is that these markets will be cheaper and more efficient, will attract the bulk of customers, and you can eventually move towards something closer to public health care. In reformer-speak, this is called "sequentialism," and all the major plans have it. But what you're seeing in these plans is the candidates attempting to create as good a health care system as an anxious public will allow. That means trading in some good policy -- like funding through taxes -- in order to retain a high level of security.