In 1957 Elizabeth Eckford and eight other black American teenagers were turned away from the Central High School of Little Rock by the Arkansas National Guard, in defiance of federal court orders.  A few weeks later, units of the United States army escorted Eckford and her colleagues into the school.

Last week, the European Court of Justice ruled that European finance ministers had acted illegally in failing to take enforcement action against France and Germany under the Stability and Growth Pact.  It is, however, unlikely that this issue will be resolved in a similar way.

For constitutional theorists, this contrast illustrates the difference between a federation and an association.   When President Eisenhower sent troops to Little Rock he demonstrated that the US government has not just the formal but the effective power to enforce its will directly in dissenting states.   The test comes when an issue arises and it is possible neither to allow individual states freedom to determine their response nor to achieve a consensus on what common policies should be.  In the United States, the treatment of black Americans has been such an issue.  In Europe, the formation of fiscal policy within the eurozone has a similar, if less controversial, character.

It makes a difference that Eisenhower was Commander-in-Chief of the world’s most powerful military machine while Romano Prodi, president of the European Commission, struggles to maintain authority amongst his colleagues.  And fiscal prudence will never enjoy the same moral imperative as desegregation.  

But the United States is exceptional among federations.  A future European army could not enforce common policies within Europe itself.  There are national armies in Canada, Australia and Belgium, but it is almost inconceivable that a dispute within these federal states would be resolved by dispatching troops to Quebec, Sydney, Antwerp or Liège.  Even in the unitary states of Spain and the United Kingdom, it is now hard to imagine that the Spanish or British government would contemplate military action in Catalonia or Scotland without the agreement of their regional authorities.  In all these instances, the alternative to agreement is the break up of the country.

Robert Kagan, the US commentator who claims that Americans are from Mars and Europeans from Venus, is right to observe a growing difference in attitudes to the coercive power of the state.   But the issue is not just, or mainly, one of foreign policy.   You see the transatlantic difference in the numbers of people incarcerated, in attitudes to capital punishment and to gun control, and in the very concept of a war on drugs or terror.  It is difficult to visualise either the siege of Waco, or the paranoid right wing responses it engendered, happening in Europe, where the notion of government as menacing to economic freedom, far less personal security, seems far fetched.  Alan Greenspan’s remark that ‘the basis of regulation is armed force’ has always seemed to me absurd. But as Ken Lay is paraded in handcuffs, Greenspan may be observing a genuine difference between a society in which economic regulation must rest on consent and one where everything that has not been prohibited in explicit terms is believed to be permissible.

Nazi aggression and tyranny, the Spanish Civil War, the notion that Britain could rule Ireland against the wishes of most of its inhabitants, are all within living memory.   The creation of modern Europe represents a conscious rejection of that history.  The absence within the European Union of a central authority with power to exercise coercion either at home or abroad is not a weakness, but the very essence of an association whose overriding motivation is a determination never again to be engulfed in the wars that created such destruction in the twentieth century.

The Stability and Growth Pact, with an empty threat of sanctions, was a mistake.   The future of European democracy is about mediation not majority rule, and its regulation about shared values not imposed rules.   The coordination of fiscal policy requires common aspirations, not mathematical formulae without moral authority.  The federal constitution of the United States is a structure unique to its time and place.  The European Union is a project no less ambitious than the United States of America, but entirely different in origins, aspirations and nature.  Its draft constitution would be a better document if it recognised that.