Amid uncertainties over whether China's combination of authoritarian one-party rule and a rapidly evolving economy can persist, an academic at the Beijing Institute of Technology notes that many Chinese intellectuals wonder whether 70 years is about as long as any single party can remain in power. The wondering comes from looking at the examples of the Communist Party of the Soviet Union and Mexico's Institutional Revolutionary Party. Uninterrupted rule by the Chinese Communist Party will hit the 70-year mark in 2019.

There certainly is an unresolved tension between China's authoritarian politics and the vibrant entrepreneurial economics that Deng Xiaoping launched more than three decades ago. The tension mainly has to do with free market economics creating independent centers of power, and power inevitably having political implications. Maybe 70 years really is about as long as anyone can finesse a way through such contradictions.

Longevity per se is probably not the critical factor in bringing one-party rule to an end. It is longevity combined with an inability by the ruling party to overcome its founding myths and to stand convincingly for something that entails a bright and successful future and that has positive resonance with the alternative power centers and the general population.

The Chinese and Soviet Communist Parties and the Mexican PRI are revolutionary parties. A fundamental problem with a revolutionary party as a ruling party is that is that its raison d'etre is stuck in the past. The party exists because it was formed to overthrow something in the past, or in the case of the PRI to consolidate the results of a past revolution. Such a party finds it hard to change its identity, in its thinking about itself and the image it has among the public, to something much different that has to do with the future. In effect its new raison d'etre, if any, is just to perpetuate its own power.

For a demonstration of how a different kind of ruling party will not necessarily run up against a time limit, look at Singapore. Despite the difference in size, the ethnic Chinese character of Singapore may make it an apt comparison with China. Singapore is in effect a one-party state; the People's Action Party has governed Singapore without interruption since independence in 1965, and for several years before that when Singapore had self-government under British sovereignty. The PAP holds all but a handful of seats in the national legislature.

The PAP is not a revolutionary party. It convincingly stands for what makes Singapore the modern success story that it is: a stunningly successful entrepot that is far cleaner—both physically and in terms of avoiding corruption—than China and also gets high marks for commitment to the rule of law. What underlies the success and what the PAP stands for is a rational, pragmatic, legal approach to public affairs. Involved in that is a strong commitment to meritocracy. Recognition of the importance of government and of excellence in government for economic success is reflected in the compensation for ministers and senior bureaucrats being among the highest in the world.

The PAP still has several more years of rule before its 70-year mark. But it is a good bet that as it approaches that mark it will not—even if Singapore does not become appreciably more democratic than it is now—elicit the kinds of doubts that are being voiced now about the rule of the Chinese Communist Party. Those doubts are expressed as China is about to transfer power to a new party chief who, whatever his talents, is a revolutionary princeling who represents ties with the past at least as much as the future.