Single payer would be ideal for most Americans, but (opponents) seem to prefer the high deductible health plans I think a single-payer system would be far more

Single payer would be ideal for most Americans, but (opponents) seem to prefer the high deductible health plans I think a single-payer system would be far more efficient, but the problem is: how do you just "shut down" a huge economic system (insurers, for-profit providers) and keep it Constitutional? They have equity in their current structures, but how do you fairly compute a "fair market value" for their market share and investments when you effectively use Eminent Domain (unless you could amend the Constitution accordingly) to dismantle an entire industry? I can imagine how Britain's NHS could be created in a time of great national unity, scarce resources, and complete Labor control, but I can't picture the mechanism by which health care could be nationalized in the present-day USA, even if a popular mandate existed.