BRUSSELS – The festering dispute between France and Turkey over a naval standoff in the Mediterranean Sea has shone a glaring searchlight on NATO's struggle to keep order among its ranks and exposed weaknesses in a military alliance that can only take action by consensus.

The dispute has also revealed NATO's limits when its allies are or are perceived to be on different sides of a conflict — in this case in Libya — especially when a major nuclear ally like France has lamented the "brain death" at the world's biggest security organization due to a lack of American leadership.

According to French accounts of the June 10 incident in the Mediterranean, the French frigate Courbet was illuminated by the targeting radar of a Turkish warship that was escorting a Tanzanian-flagged cargo ship when the French vessel approached.

France said it was acting on intelligence from NATO that the civilian ship could be involved in trafficking arms to Libya. The Courbet was part of the alliance's operation Sea Guardian, which helps provide maritime security in the Mediterranean.

In a power-point presentation to French senators on Wednesday, which angered the French officials, Turkey's ambassador to Paris, Ismail Hakki Musa, denied that the Courbet had been "lit up" by targeting radar and accused the French navy of harassing the Turkish convoy.

The French defense ministry rushed to release its version of events and underline that it would not take part in the operation until the allies had recommitted to the arms embargo on Libya, among other demands.

At the heart of the France-Turkey quarrel is the question of whether NATO allies should respect the U.N. arms embargo for Libya. NATO Secretary-General Jens Stoltenberg said last month that the alliance "of course supports the implementation of U.N. decisions, including U.N. arms embargoes."

In normal times, the United States — by far the most powerful and influential of the allies — could be expected to bring its partners into line. But the past four years, with President Donald Trump at the helm in the U.S., have been extraordinary times for NATO.

With no firm U.S. guiding hand, divisions among the allies over how Libya should be handled, and a decisionmaking process that requires everyone to agree — even on what they should talk about — it's difficult to see when NATO might debate the embargo question in earnest.