Europeans will soon consider a proposed constitution for the EU that is very different from the US Constitution. The US is the oldest and largest surviving constitutional republic -- a nation that has experienced a larger increase in area, population, and income; absorbing people of more diverse racial, ethnic and language backgrounds than any other contemporary nation. So Europeans are well advised to understand and consider those characteristics of the US Constitution that provided the political and legal framework for the American success story. \nSeveral characteristics of the US Constitution have contributed to its relative success and survival as a body of foundation law. The preamble, for example, describes the objectives of the Constitution in only 52 words of forceful, declaratory and quite general prose, which, by itself, provides no authority for any specific political decision. \nThe main text, in only seven articles, describes the powers authorized to the several branches of government and the powers denied to the federal government or the states as few, brief, and well defined. All residual powers are reserved to the states. \nAnd the Bill of Rights, with one exception, is a list of the rights of individuals against the state, not a list of claims by individuals on services to be provided by the state; the one exception is the right to a trial by jury. All residual rights are reserved to the people. \nThe proposed EU constitution is very different in several dimensions. The preamble goes on and on for 293 words to describe the shared values and objectives of the Union; this is wholly unnecessary and sure to provoke continued controversy. \nOne sentence alone, for example, commits the Union to "work for a Europe of sustainable development based on balanced economic growth, with a social market economy aiming at full employment and social progress," a sentence that includes at least five ambiguous terms. \nThe proposed constitution has more than 400 articles but leaves several important issues unresolved. \nThe relation between the Union and the member states, for example, is not clearly defined; one article suggests that the Union could use its power outside its exclusive authority if some unspecified body decides that the Union could do it better than a member state. \nAnother article authorizes the Court of Justice to give preliminary rulings on the interpretation of Union law but without identifying what body has the authority to make a final ruling on these issues. \nThe most important difference between the US Constitution and the proposed EU constitution, however, is the concept of rights. \nThe US Bill of Rights is a list of individual rights against the state. In contrast, the Charter of Fundamental Rights, which constitutes Part II of the proposed EU constitution, includes a long list of rights to services provided by the state. Such rights, for example, include education, a free placement service, paid maternity leave, social security benefits and social services, housing assistance, preventive health care, services of general economic interest and high levels of environmental and consumer protection. \nThese claims on the state represent the most important potential tension in the Union. On the one hand, the proposed EU constitution states that the "Free movement of persons, goods, services and capital, and freedom of establishment shall be guaranteed within and by the Union ... [and] any discrimination on grounds of nationality shall be prohibited." \nFine. On the other hand, any citizen of the Union seems to have a claim on a wide range of social services wherever that person chooses to live. This will lead to either a massive movement of people to states with a higher level of social services or the harmonization of these services among the member states. \nThe only way to resolve this potential tension is to allow each member state to restrict access to social services on the basis of such personal conditions as the number of years of work in that state and the absence of a felony conviction. Unless that happens, the EU will become a massive, harmonized welfare state. \nAs in the US, the proposed EU constitution doesn't deal well with the inherent conflict between nondiscrimination and affirmative action. \nThe EU constitution states that the "Equality between men and women must be assured in all areas, including employment, work and pay," but this "shall not prevent the maintenance or adoption of measures providing for specific advantages in favor of the under-represented sex." \nFor the moment, in both the US and the EU, discrimination against people is generally illegal but discrimination in favor of some people is sometimes required. This minor madness, hopefully, will not last. \nA final point: The text of the proposed EU constitution is pretentious. Many of the substantive provisions are described as if they were derived from some first principle, as if the crafting of a constitution is some form of algebra rather than the result of political negotiation and agreement. \nFor example, the text talks about the principles of loyal cooperation, conferral, subsidiarity, proportionality, solidarity, democratic equality, representative democracy, participatory democracy, and on and on. \nBroad agreement on the substantive provisions of a constitution is necessary to its effectiveness. Broad agreement on principles is not, because many people may support the same substantive provision for quite different reasons. On these issues, I suggest that Madison is a better guide to an effective constitution than is Descartes. \nEuropeans should be careful about any major political structure that is presented for their approval, particularly a constitution that was originally presented as a treaty among the member states but now appears to be more like the constitution of a European nation. \nEven those who favor the major provisions of the proposed constitution should be careful to ensure that the constitution limits the authority of the EU to define its own powers, because all governments seek broader powers than first authorized. \nOver time, an imperfect Europe of national states -- bloodied but hopefully wiser -- may be a better protection of liberty than approving the proposed constitution in the hope for a more perfect EU. \nWilliam Niskanen is chairman of the Cato Institute, www.cato.org, in Washington.