Mexico's attempts at health reform have been extremely convoluted. The first decentralization reform of its health care system was a response to requests from the WB and the IMF to free central funds to pay its external public debt during a world recession. After 6 y, only 14 states had agreed to be decentralized. The remaining states understood that decentralization was not accompanied with the additional funding needed to undertake the new responsibilities that decentralization was transferring. The decentralized states soon protested the minimal transfer of decision-making power as well as the demands made by the central government for additional state funds.
The next administration (1988–1994) understood that the cost of decentralization had been high and its achievements negligible, and the decentralization process was halted. This administration took a different position on how to develop the country politically and economically and decided to centralize all new social service programs in the president's office. Politically, the results were catastrophic and political analysts forecasted the end of the PRI hegemony.
Recognizing that political changes were needed to remain in power, the subsequent PRI administration decided to reduce political authoritarianism. One measure it took was to transfer decision-making power and funding to the states, thus initiating the second decentralization of the health sector. There was also an attempt to implement a reform along the lines of the structured pluralism model, which was derailed by the IMSS labor unions.
Finally, new efforts to privatize the delivery of care commenced when SP was launched by PAN at the start of this century. Unfortunately, the designers of the SP ignored the implementation constraints of a program prepared without concurrence from the states. In particular, the decentralized states did not have to adhere to the requisites mandated by the MoH. The ministry soon realized that decentralization was impeding the implementation of SP, and although government documents continued to mention decentralization since the inception of SP, no attempts have been made to advance decentralization further.
One state policy maker in Sonora explained the designers' failure to foresee implementation problems when he referred to the designers: “[as researchers] experimenting with models, always generating ideas that were not very practical… did not have their feet in the real world… kids from Harvard with no social experience, out of touch with the people with needs” [40, p. 192]
. Consequently, only a few states had the planning resources to design an insurance scheme for the poor, and now Mexico has 32 variations of the SP, with unforeseeable equity and portability problems.
There are also design incongruities within the SP. It is a voluntary program that promises to have the entire population insured by 2010. Five years after its inception, however, less than 1% of eligible families pay premiums, and 74% of the premiums that are collected come from the state of Tabasco; in all other states practically all the enrollees have had their fees waived. According to the SP designers, the 35 million people who are unenrolled but eligible (most of whom will have to pay premiums) should be enrolled by 2010. However, this group may prefer to continue paying copayments at state facilities unless they perceive a drastic deterioration of quality in these services. This deterioration could occur if the MoH reduces the allocation of resources to the state health services. If such a policy takes place, the 17-y decentralization effort to strengthen the states' health systems would be lost. Families could also decide to join the IMSS program for the uninsured, an option that has been available for a number of years but that very few have chosen, probably because the concept of insurance and prepayment of premiums are not part of the culture among less affluent people.
Although SP must improve in many areas to reach its goals, its designers highlight successful aspects of the program and cite the millions of people enrolled in the program. These successful aspects are inevitable; poor families are insured at no cost as a result of the massive allocation of additional resources that has created two parallel state-run health care systems for the uninsured. Increasing health funding in Mexico is important, but independent evaluations suggest that SP is not the most successful model to achieve equity, efficiency, and quality care.
SP enrollees have always had access to public health services with a copayment. Exempting the poor from copayments might have been a less expensive way to accomplish the same end result as the implementation of SP. Better and more equitable results, probably at a lower cost, might also have been achieved by helping the IMSS to increase its efficiency and workforce productivity, and by expanding its programs for the uninsured. Instead, according to observers, SP may reduce employers' incentives to offer Social Security coverage 
, and SP may expand at the expense of IMSS 
, especially now that the MoH's priority is the SP 
Given the lack of continuity for social programs in the past, it is hard to foresee the future for SP with any degree of certainty. Future governments could decide to transfer SP to IMSS or to state health departments to promote a more complete decentralization. Alternatively, they might continue to provide subsidies for those already enrolled in the SP. If the SP program continues to build on the principles of the Colombian reform, however, the effects of SP on the Mexican health care system may not be necessarily positive.