If you do start with universal mandates and do not have an extremely strong regulatory position in place as to cost management on the insurance company side (which Clinton's plan really doesn't have, it has fairly weak cost controls that aren't significantly different than Obama's), what you've done is remove any incentive for insurance companies to cost-manage or cut front-end costs since their revenue stream is protected by the US government.

The risk pool is fully universal for children, so your argument makes no sense there. There is a mandate on coverage for children and not adults because there is already an existing framework for providing extremely low-cost coverage for children (SCHIP, for which Clinton gets some level of credit, and other programs), whereas there are not such frameworks in place for adults.

Again, without extremely stringent controls on front-end costs, what you're doing with mandates is not "making the risk pool universal", what you're doing is forcing low-income people to fund insurance companies by force of government. When you hear reports that Obama's plans will leave X million not covered, they're not referring to healthy people with decent incomes. Those people are overwhelmingly likely to opt in because costs are low, benefits are good, and they have the income to support it (versus more expensive partly-employer-funded options -- my "employer-paid" coverage costs me hundreds a month).

No, the people that they're arguing are left out are poor people with iffy medical histories. Such people definitely deserve coverage too. But including them does not improve the risk pool, it makes it worse. And for healthy poor people it actually significantly harms them, because they're now required by legal mandate to pay for health care that they do not need. For unhealthy poor people it's still a net loss, because we're shifting funding from emergency rooms to the backs of the poor. Yes, emergency room care is the worst way to provide health care, but this isn't a better way for poor people.

If you want a scheme like Clinton's to work, you need the "enforcement mechanism" to be an income threshold such that anyone who cannot pay for health care by some reasonable standard has it provided for them without mandates, sanctions, wage garnishment, etc. That of course starts to somewhat approach single-payer, at least for the poor.

In the absence of such a requirement, what you're really doing is mandating that poor people fund health insurance companies to their own detriment. That's hardly a progressive solution to health care.

Obama's plan, while flawed, at least provides some mechanism for cost containment and refuses to treat the poor as a mandatory profit center for the insurance industry.