On paper, having one state agency as the exclusive purveyor of health care for 40 million Californians would seem to make sense, replacing dozens of federal, state and private systems and their often bewildering financial and managerial peculiarities.

Centralized health care seems to work fairly well in other developed countries, such as Canada and the United Kingdom, with per capita costs somewhat lower than those in the United States.

The notion has been kicking around in California political circles for years and at one point, the state Senate passed a single-payer bill, although it stalled in the Assembly for lack of a financing mechanism.

The idea resurfaced last week with the introduction of two measures. One to create the framework for such a system in California, the other to ask voters to levy tens of billions of dollars in new taxes, mostly on affluent taxpayers and businesses, to pay for it…