I'm not the first to observe that the physical nature of movement internationally has become much easier in the past century. But in other aspects the movement of people has become much more difficult. Immigration laws are constantly being revised to control the physical borders of a country, but naturalisation and citizenship regulations control a nation's invisible borders.

As the European Union becomes more operational, its residents will move easily across borders and hold two identities, national and supranational. European identity – despite energetic efforts to promote the idea of a European "demos" – will remain something bureaucratic. The national identity, one usually derived from geographic location, will be more difficult to define.

Yet national governments still regard citizenship as something precious, and guard it jealously from interlopers. France's interior minister, Nicolas Sarkozy, announced new laws on 9 February designed to make French citizenship more difficult to obtain. As Europe becomes one, national citizenship may come to mean less and less to those who are already citizens of a European country and more and more to those from the global south who would like the opportunity to fully share in Europe's riches.

This past month, the international spotlight has been on a little Scandinavian country, famously generous Denmark, known for its huge distributions of international aid, liberal social policies and one of the most difficult to obtain passports in Europe. What Denmark has, it may give away liberally but it does not share. As Saeed Taji Farouky mentions in openDemocracy's compendium of responses to the "cartoon war", Denmark's rules regarding citizenship are among the most restrictive in the European Union. Only Austria and Spain are more so. In Denmark, one cannot gain citizenship automatically by birth nor hold dual citizenship. One must be a resident of Denmark for ten years before being eligible for naturalisation.

KA Dilday worked on the New York Times opinion page until autumn 2005, when she began a writing fellowship with the Institute of Current World Affairs. During this period of the fellowship, she will be travelling between north Africa and France.

Also by KA Dilday on openDemocracy:

"The freedom trail" (August 2005)

"Art and suffering: four years since 9/11" (August 2005)

"Rebranding America" (September 2005)

"Judith Miller's race: the unasked question" (October 2005)

"France seeks a world voice" (December 2005)

"A question of class" (January 2006)

If you find KA Dilday's writing enjoyable or provoking please consider commenting in our forums – and supporting openDemocracy by sending us a donation so that we can continue our work for democratic dialogue

Before 11 September 2001, the trend of policies concerning citizenship in many European countries was toward increasing liberalisation (some of these policies were decided before yet became effective after that date). Many are Byzantine and convoluted: some require complicated manipulations to conform to what may be the letter of the law if not the spirit. In some cases, the letter of the law is not as important as the spirit. However, in recent years, there seems to be a snap back. It is possible that other countries in Europe will follow France's example and make their policies more rigid. Most of the changes in the past twenty years that have limited naturalisation seem specifically focused on immigrants from Africa, both northern and sub-Saharan, and in the case of Germany, those from Turkey.

These questions – who has the right, is fit, qualified, or deserves to be one of us? – will be at the heart of the new Europe. And all of these ways of viewing citizenship are loaded with opportunities for racial and religious prejudice. Now entrance to a country means not only free passage within that country, but across all twenty-five member-states of the European Union.

Even if Denmark guards its nationality closely will that matter if say, Italy does not? Being technically French or German or Bulgarian will mean less and less logistically. Holding both Norwegian and Italian nationality will be less and less advantageous. The borders are disappearing on the European continent and at the same time the gates that guard the continent are being reinforced. Yet at the micro level, nations are still asking: what does it mean to be Danish or German or French?

There is a great distinction in Europe between laws of blood and soil. The most democratic method has been to give citizenship to those born in a country. Yet very few countries in Europe hold this principle as unassailable as the United States does (for now). Most often, citizenship tests focus on myriad ways of discovering whether a person has integrated into the culture.

The most common of these is the ability to speak the national language. This focus on language can be found in the naturalisation requirements of Luxembourg, the Netherlands, and Portugal; Finland and Spain also have language stipulations (in Finland one must speak Swedish or Finnish). In the Netherlands, fears over the predicament of a Dutch language ignored or spurned by many of its immigrants have even led to a proposal by interior minister Rita Verdonk that the speaking of Dutch in public places be mandatory.

In Denmark, the test for naturalisation requires that one be able to hold a conversation in Danish, and with a natural accent. But does it matter to a Romanian who will soon have the right to work in Denmark – if the country's planned accession to the EU, along with Bulgaria, goes ahead in January 2007 – if she speaks Danish, heavily-accented or not? In any case, people who travel to Scandinavia know that it is quite possible to conduct almost all daily business in English and to find work with companies which routinely operate through the medium of English.

In France, at least, the gates are coming down. In the wake of the riots in France in October-November 2005, Nicholas Sarkozy introduced a law proposing a "points" system to prospective immigrants, rating them on skills, field of study and country of origin. In a country where many of the citizens speak Arabic, a legacy of France's colonial past, would it make more sense to make Arabic one of the national languages? But to some an immigrant's desire to hold on to a native language is seen as serving two mistresses (or more likely simply the wrong master) and then one wonders if it is fealty to another country that is at issue or if it is just fealty to the wrong country?

Yet why shouldn't one have to choose fealty and allegiance to a particular country? Is it right to profit from the benefits of two nationalities? In Germany for example, dual citizenship is not permitted at the time of acquiring German citizenship. If a youth holds dual nationality she must make a choice at the age of 23. And naturalisation requires renouncing citizenship. Many Turks remain in Germany for years as non-citizens, never fully participating in civic life. Policies such as these are creating nations within nations within the European supra-union. Situations such as these are neither desirable nor tenable.

Each country in Europe has its own particular bête noires in regard to citizenship, and each will be forced to examine these policies as the rules of the European Union become more dominant. The question can no longer be what does it mean to be Danish, but what does it mean to be European? Each national border guard seems to have a different answer.