Barack Obama heads to Britain and Europe in two weeks' time as the leader of the first U.S. Administration to wholeheartedly back the creation of a federal Europe. In contrast to earlier U.S. administrations, including those of George W. Bush and Bill Clinton, the Obama administration is avowedly Euro-federalist in outlook, and is keen to help build a European Union defense identity as well as support the foundations of a European superstate in Brussels.

This dangerous shift in U.S. policy is a betrayal of both U.S. and British interests that will threaten the long-term future of the Anglo-American Special Relationship, weaken the NATO alliance, and undermine the defence of British sovereignty in Europe. It will also undercut opposition across the EU to the Treaty of Lisbon, including in countries such as Ireland, Poland and the Czech Republic, and may set the scene for a major confrontation between the Obama White House and a future Conservative administration in London.

A Eurosceptic Conservative government led by David Cameron, committed to halting further European integration, will find itself increasingly at odds with a left-of-centre U.S. administration that is actively working against the principle of national sovereignty in Europe. In light of this, the current enthusiasm of many British conservatives for the changing of the guard at the White House is hugely misplaced.

The Bush Administration was sharply divided over Europe, with then Secretary of State Condoleezza Rice backing the European Constitution, but her pro-Brussels instincts were strongly opposed by key figures in the White House and the Pentagon. Bush himself was no supporter of a Franco-German dominated Europe, and worked hard to build up a counterweight of pro-American nations among the new EU members from eastern and central Europe.

In contrast, President Obama's government will strongly back the European Security and Defence Policy, the Lisbon Treaty and the Common Foreign and Security Policy, and will seek to strengthen French and German leadership at the heart of a united European Union. It has appointed several prominent supporters of European federalism to key positions in the Pentagon and State Department, including the new Undersecretary of defense for Policy, Michèle Flournoy, and Philip H. Gordon, the next Assistant Secretary of State for European and Eurasian Affairs.

Flournoy, who holds one of the most powerful positions in the Pentagon, is a leading supporter of U.S. backing for an EU defence policy, and co-authored a major 2005 study strongly advocating American support for a unified European defence structure. Gordon, who will be the most senior administration official on Europe, has written that America must "support the European project", and that "the challenge for U.S. policy is to encourage Europe to develop the cohesion and capability to become a true transatlantic partner." He is also a prominent backer of the defeated EU Constitution, and has pushed in the past for British membership of the Euro, warning the UK that "fully in Europe, Britain has every chance to remain America's preferred and privileged partner. Marginalized from the EU, Britain could find itself less influential in Washington as well."

The Obama Administration has already made major concessions to Paris over President Sarkozy's decision for France to rejoin the NATO integrated command structure. The French have been given two major positions at the helm of the Alliance, a move that will significantly enhance the drive towards a European defence component within NATO. Vice President Joe Biden has clearly indicated that the United States will support "the further strengthening of European defense" and an "increased role for the European Union in preserving peace and security." When he travels to Europe, President Obama is expected to deliver the same message.

Significantly, while wooing both continental Europe and Russia, the new U.S. administration has been largely indifferent to the Anglo-American alliance, with an appallingly handled reception for the British Prime Minister when he visited the White House earlier this month, and the recalibration of the special relationship as a "special partnership". Even a bust of Sir Winston Churchill has been unceremoniously thrown out of the Oval Office. A distinctly undiplomatic State Department official involved in the planning of the Obama-Brown meeting was quoted by The Sunday Telegraph as saying that "there's nothing special about Britain. You're just the same as the other 190 countries in the world."

There is a chance the Obama Administration will eventually wake up to the reality that American support for a federal Europe will backfire. Such a naive approach will not result in European countries spending more on defence, or in a more effective Europe. It would also undermine Washington's ability to mobilize international coalitions. Under a unified EU foreign policy, U.S. allies would lose the freedom to decide where and when they can fight alongside America.

As they approach the transatlantic alliance, President Obama and his aides should heed the advice of a former prime minister and great friend of the United States who fought to defend the Special Relationship and maintain British sovereignty in Europe. As Margaret Thatcher put it, "that such an unnecessary and irrational project as building a European superstate was ever embarked upon will seem in future years to be perhaps the greatest folly of the modern era."

Nile Gardiner is Director of the Margaret Thatcher Centre for Freedom at the Heritage Foundation in Washington, DC.