In response to my question on the Medicaid waiver being sought by the Carcieri administration, commenter “mrh” responded…

I’d say that in general, “liberal Democratic” plans for universal health care don’t promise to “put people on waiting lists for treatment, and limit the duration and scope of services.”

…to which commenter “bobc” responded…

You’re right they don’t “promise” to “put people on waiting lists for treatment, and limit the duration and scope of services.” But of course they will!

Let me further Bobc’s point with a few examples…
1. This is from New York Times columnist Paul Krugman, who I believe is considered mainstream (maybe even a centrist!) by most liberals…

A national health care system will also be better at rationing when the time comes, but that hardly seems like the prime argument for adopting such a system today.

Krugman is for having government limit access to medical care, as he says, “when the time comes”, but doesn’t want people to know about this rationale for getting government into the healthcare business until it’s too late. Many problems here.
2. A little more locally, Froma Harrop of the Projo recently wrote this about the Massachusetts universal healthcare mandate…

There have been glitches, the main one being that the plan will cost $129 million more than projected. That sounds like a lot of money, but bingo, the state could save $160 million simply by enrolling all its Medicaid members in managed-care plans. Shortfall averted with $30 million left over.

If the point of “managed care” in this setting isn’t to give government bureaucrats the power to deny treatment, then how exactly does it work to control costs? (And remember, specifically for this example, Froma Harrop doesn’t believe that preventative medicine does anything to lower costs, so that can’t be the answer).
3. Moving out a bit towards the fringes, William Saletan of Slate Magazine believes the government-run healthcare should be used to reduce age inequality, i.e. the fact that genetics allow some people to live longer lives than others. I don’t think this is mainstream thinking, but that doesn’t mean that someone who believes as Saletan does couldn’t end up in charge of a rationing or managed care system, once one was constructed.
We can always argue how much any subset of liberals is speaking for all liberals, if it’s possible to speak for all liberals, etc. However, it is abundantly clear that an intersection does exist of people who 1) vote “Democrat” on a regular basis 2) want government to be more strongly involved in setting an individual’s range of healthcare options and 3) want that stronger influence to be there to control costs by denying care.
If this is truly fringe thinking (even beyond Saletan), the wider world of liberalism should be more vocal about it.