New Prime Minister David Cameron has a major opportunity to transform and rejuvenate British leadership on the world stage. As the world’s fourth-biggest military force and sixth-largest economy, the United Kingdom may not be a superpower, but it remains a world power.

There can be little doubt that the domestic agenda will be the Conservative-led coalition government’s main focus—a stagnant economy, rising unemployment, and a spiraling budget deficit remain U.K. voters’ primary concerns. Cameron should not, however, back down from advancing powerful British leadership on the world stage. He will have a strong foreign and security team at his disposal, with William Hague as Foreign Secretary and Liam Fox as Defense Secretary.

After three years of lackluster helmsmanship from Gordon Brown, Britain’s international presence needs to be revitalized. At the same time, Barack Obama’s failure to assert powerful U.S. leadership offers the Conservative leader a major opportunity to flex British muscle. The new government should not be afraid to aggressively assert a British footprint, both in Europe and across the globe.

A conservative foreign policy should rest on four key principles: (1) the preservation of the Anglo–American Special Relationship and the transatlantic alliance, (2) the defense of British national sovereignty, (3) the firm projection of military power in the defense of the national interest, and (4) the advancement of freedom and liberty. All four principles should be underwritten by a strong national defense, necessitating a significant increase in defense spending above its current historically low level of just 2.1 percent of GDP.

1. Advance the Special Relationship

The heart of a Conservative-led foreign policy must be the Special Relationship, the most important and successful partnership of modern times. It is the beating heart of the free world and the engine that drives the global war against Islamist terrorism. Under Obama and Brown, the Anglo–American alliance has been weakened through a combination of Washington’s indifference and a series of strategic errors by London, including the appalling release last year of Libyan Lockerbie bomber Abdelbaset Ali al-Megrahi. Disappointingly, the U.S. President has never even mentioned Britain in a single major speech, both before and since entering the White House.

The next Prime Minister should make the full restoration of the alliance with the United States a top priority. He should also ensure that Britain’s freedom to stand shoulder-to-shoulder with America is not constrained by the Treaty of Lisbon and the relentless drive toward ever-closer union in Europe.

2. Stand Up to the Rise of a European Superstate

The rise of a European Union superstate, with a common foreign and security policy as well as a European security and defense policy, directly threatens both British and American interests. The Obama Administration should be sent the message that its strong support for a federal Europe is misplaced and that a Conservative government will fight against any efforts by Brussels to take further powers away from London. This statement should include a complete rejection of an EU defense identity and a supranational EU foreign policy as well as any dilution of the NATO alliance.

3. Invest in Defense and Be Prepared to Use Force Where Necessary

Under the Conservatives, Britain should be prepared to wield military might independent of the EU—and with the appropriate level of defense spending to back it up. Cameron has shown a strong commitment to the 10,000-troop British mission in Afghanistan, rejecting the notion of a timetable for the withdrawal of NATO troops. He should also be prepared to use force if necessary alongside the U.S. to halt the rise of a nuclear-armed Iran, in addition to pressing for a range of tougher European and United Nations Security Council political, economic, and military sanctions against Tehran.

4. Support the Cause of Freedom on the World Stage

Finally, a Conservative government should pursue a foreign policy that, at its core, supports freedom across the globe. Such a commitment includes supporting the aspirations of opposition movements in tyrannies such as Iran, Burma, and Zimbabwe and standing up to dictatorial regimes that suppress their own people and in some instances also act as state sponsors of terrorism.

Cameron should avoid embarking down the same engagement path traveled by President Obama, which has succeeded only in emboldening America’s enemies and weakening U.S. strategic power. He should forthrightly defend political dissidents who are fighting for freedom, from Moscow to Harare to Tehran, and studiously avoid the appeasement of tyrants. A Conservative administration should also advance a free trade agenda that supports the growth of economic freedom across the world and confronts protectionist policies on both sides of the Atlantic.

Cameron Should Look to Churchill and Thatcher as Role Models

Though largely untested in the foreign policy arena, Cameron has the potential to be an international statesman of significant stature. In order to realize this promise, however, he should be prepared to advance an agenda that projects strength—not weakness—and allocates the military resources required for Britain to operate successfully as a world power. He should look not to Barack Obama as a role model but to Winston Churchill and Margaret Thatcher, two decisive and iron-willed leaders who took great pride in their country’s past while unashamedly advancing the national interest.

The world needs strong British leadership, especially at a time when Washington is hesitating to take a strong stand on several critical fronts. Britain has a vital role to play in blocking the rise of a nuclear Iran as well as winning the war in Afghanistan. A Conservative government should strengthen Britain’s alliances with the U.S. and NATO while enhancing strategic partnerships with rising friendly powers such as India.

Under Gordon Brown, Great Britain punched well below its weight as an international actor, with the exception of its role in Afghanistan. For a nation with a proud history of global leadership and a rich heritage that spans much of the world, now is the time for that to change.

Nile Gardiner, Ph.D., is Director of the Margaret Thatcher Center for Freedom, a division of the Kathryn and Shelby Cullom Davis Institute for International Studies, at The Heritage Foundation.