France will rejoin NATO as a full member at the alliance's 60th-anniversary summit in France and Germany this weekend, a move observers say is aimed at strengthening not only French military cooperation with the United States but also joint European defense efforts.

In 1966, Charles de Gaulle had France leave NATO's military command because he felt Washington dominated the alliance; he even threw NATO's headquarters out of France, roughly two decades after Allied forces -- mainly U.S. and British troops -- liberated the country from the Nazi occupation.

This weekend, after more than 40 years, NATO leaders will welcome France back into the alliance at a summit taking place in Strasbourg, France, and Kehl, Germany, co-hosted by French President Nicolas Sarkozy.

The Washington-friendly Sarkozy signaled that he might bring France back into NATO as early as 2007; he then finalized the plan by getting parliamentary backing last month.

It's a move that has been welcomed by Washington and several European powers; it carries symbolic significance, and it has proven quite controversial in France. However, it won't radically alter NATO.

France is the fourth-largest contributor of troops and has long backed NATO financially. It has taken part in several major NATO missions, including those in Kosovo, Bosnia and Afghanistan.

Rejoining NATO isn't an entirely new strategy; former President Jacques Chirac had planned to do so in the 1990s, but the price he claimed in exchange was too high. Washington wasn't willing to give France control of NATO's vital southern command, a post traditionally held by U.S. generals.

Things have changed since then; Sarkozy has been eager to improve relations with Washington and has argued that his country could only benefit from rejoining NATO's military command. The reasoning in the Elysee Palace is, "If we send so many troops to NATO missions, why not have our generals take part in the decision-making?" Engaging fully in organizations like the European Union and the U.N. Security Council, Sarkozy argues, has strengthened France's global position.

In France, critics are nevertheless crying foul. They say Sarkozy is sacrificing French autonomy and the traditional backing for a joint European security and defense identity.

"France is sending a signal of withdrawal into the Western sphere," said Segolene Royal, the former presidential candidate from the Socialist Party.

Critics also bash as merely symbolic the announced trade-off France is getting -- leadership of the Allied Command Transformation project in Virginia and a regional command in Lisbon, Portugal.

But Sarkozy is looking beyond the trade-off, said Martin Koopmann, head of the Genshagen Foundation, a think tank focusing on French-German politics. And his move is aimed at benefiting European defense rather than hurting it, Koopmann said.

"Sarkozy is trying to end the strong division that has formed for many years between the trans-Atlantics and those who favor a joint European security and defense policy, by increasing mutual cooperation," he told United Press International in a telephone interview.

"Besides the United States, this concerns mainly the Central and Eastern Europeans," he added. "These countries are closely allied with the United States, but you eventually need their support and their troops if you want to remain credible and built up a strong European defense unit."

Sarkozy also wants France to take part in shaping NATO's post-Cold War transformation and influence the alliance's strategy change for the crucial war in Afghanistan, where 2,800 French troops are taking part even in combat missions -- a responsibility neighboring Germany is still dodging.