As Toby Harnden first reported in The Daily Telegraph, the U.S. president will meet with David Cameron on Wednesday ahead of the G-20 summit in London. The decision to meet with the Conservative Party leader is an unusually smart foreign policy move by the new U.S. administration after a series of poor decisions by the White House with regard to the Anglo-American alliance.

These have ranged from throwing a bust of Churchill out of the Oval Office to giving the Prime Minister a collection of unplayable DVDs. The special relationship has been rashly recalibrated as a "special partnership", and Britain has been insultingly described by a senior State Department official as "just the same as the other 190 countries in the world". These were not just throwaway remarks - they revealed a deep shift in thinking which is taking place in the US Executive Branch with regard to not only the US-UK alliance but also Europe.

Obama's advisers are well aware that the Conservatives have gained a commanding lead over the Labour Party in the polls, and short of a dramatic turnaround in political fortunes, they predict Cameron will be in Downing Street by June next year. This is a significant strategic win for Cameron and his leadership team including William Hague and George Osborne, who are also expected to meet with the president. For years in opposition the Conservatives failed to gain a foothold in Washington, ceding influence to Labour. That period in the wilderness is over.

As the Conservatives edge closer to power they will need to project a stronger presence on the world stage, and a privileged meeting with the leader of the free world sends a clear signal that British Conservatives are back as a force to be reckoned with in international affairs. The meeting will magnify Cameron's standing as a potential Prime Minister, and will generate significant publicity for him with a broader international audience, including millions of Americans. It is also an important opportunity for the Conservative leader to express clear reservations over the drift in US thinking with regard to transatlantic relations.

On the surface, the Democrat and Tory leaders share a good deal of mutual ground. Both Obama and Cameron are relatively young, charismatic politicians who have risen to prominence on the promise of change for their respective countries. In terms of personality, the US president has far more in common with the youthful Cameron than he has with the significantly greyer Gordon Brown. There was little chemistry between Obama and Brown when they met in the Oval Office in March, and at times the meeting looked distinctly awkward and uncomfortable.

On foreign policy, it is hard to discern any sharp divisions between the new US administration and the Conservatives on issues ranging from the Iranian nuclear crisis to the Middle East peace process. Cameron is wary of backing the deployment of more British troops to the front lines of Afghanistan until the military goals are more clearly defined, but remains firmly committed to the US and NATO-led operation to defeat the Taliban.

It is on the question of European policy that a clear transatlantic divide may emerge between the United States and a Cameron-led Britain. President Obama heads the first American administration to wholeheartedly support the European Project, or the notion of ever-closer union in Europe. The Bush administration was split between the pro-European State Department, and the more cautious Pentagon and White House, while the Clinton administration fought hard against the development of a European defence identity.

In marked contrast the Obama administration is united in its backing for the EU Common Foreign and Security Policy, the European Security and Defence Policy as well as the Treaty of Lisbon, all of which will undermine democracy in Europe and undercut traditional alliances such as NATO. Both Vice President Joe Biden and Secretary of State Hillary Clinton have spoken out in favour of European integration, a position which is almost certainly shared by the president himself.

In just over a year the Obama team will likely face the most Eurosceptic ruling parliamentary party since Margaret Thatcher held office. The Conservatives have pledged to halt the drive towards further European integration as well as the erosion of British national sovereignty. They will have to deal with an American government that at present is more likely to side with Brussels and Paris on this issue than with its natural ally in London. The chasm between the United States and Great Britain over Europe will be a huge one that will be difficult to bridge unless the Obama administration changes course.

In his brief meeting with the US president, David Cameron will naturally seek to build strong ties with a White House he may ultimately work with as Prime Minister. He must not be reticent though about reaffirming the principle of British sovereignty in the European Union, and conveying a clear message to President Obama that US support for a federal Europe is neither in the American nor British national interest. As the Conservatives prepare for power, the preservation of the Special Relationship and the defence of the transatlantic alliance should be top priorities.

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