We now enter the heart of our analysis of political families. Before examining each one in detail, however, we must address a fundamental question: how should we define a political system? Take socialism as an example.

Should we define it by its stated intentions (justice, well-being, emancipation), or should we instead define it by its fundamental structure, namely whether it gives primacy to the individual or to the state?

Milton Friedman wrote:

In other words, Friedman gives priority to what we might call empirical analysis: focusing on the visible consequences of a system rather than on political promises and programs. This echoes what Frederic Bastiat taught when he argued that the good economist is one who sees the effects of a policy not only in the short term but also in the long term, and not only on a particular group but on the entire population.

Friedman warns us against the danger of relying solely on intentions. Policies motivated by generous intentions can have unforeseen or harmful consequences when they neglect a rigorous analysis of human incentives and behavior. For example, social assistance programs funded by the state (that is, by the taxpayer) risk producing perverse effects: they create no incentive to work, they generate economic dependency, and they amount to a form of spoliation since the money must first be taken from those who produced the wealth. For Friedman, measurable results, such as economic growth, poverty reduction, or efficiency, must take precedence over intentions, because the latter, however noble, do not guarantee success.

Structural or practical definitions focus on how political systems actually function and on their observable characteristics. Socialism, for example, is characterized by the omnipresence of the state, which regulates, plans, and controls. That is a fact, and it matters far more than the declared intentions of fraternity or solidarity. Libertarianism, on the other hand, is defined by minimal state intervention in the economy and in private life, tending toward the primacy of individual freedom and the free market.

In contrast, intentional definitions rely on the stated motivations, goals, or intentions of individuals or groups. Socialism presents itself as pursuing "social justice" and solidarity. But if we rely on intentions, things become blurred, because everyone claims to favor justice; everyone invokes the sovereignty of the people. Yet "the people" remains an extremely abstract term, and therein lies the trap.

Our analysis will therefore privilege the structural approach, which allows for a more objective evaluation of political systems based on their measurable results and concrete means rather than their proclaimed intentions. On the Nolan Diagram, the bottom of the frame (pure statism, tending toward totalitarianism) will be treated somewhat separately, since it is less a political ideology than a social system. The three quadrants above (socialism on the left, centrism in the middle, conservatism on the right) and libertarianism at the top will each be examined through this structural lens.

Structural analysis serves as a critical tool. It allows us to evaluate political systems according to their real results, not their promises. Intentional definitions, by contrast, create a conceptual confusion in which all systems claim to pursue similar objectives (justice, equity, freedom), making them impossible to distinguish from one another. We must therefore attend to the empirical, measurable consequences of a political system, as well as to the means it employs. It is through these that the true nature of a political system reveals itself, beyond the rhetoric of intentions or programs.