At the heart of NATO, the world’s longest-standing security alliance, is the notion that an attack on one is an attack on all. But with many in Europe doubting a Trump-led United States will really come through for them,

France will consider extending the protection of its nuclear arsenal to its allies, French President Emmanuel Macron said Wednesday, while warning that Europe needs to be ready for the United States to not “remain by our side” in the Ukraine-Russia war.

"In the current situation, the French and British nuclear forces are a complement to U.S. extended deterrence, but they would not constitute a viable solution in the event of an abrupt withdrawal of U.S. nuclear forces," the Washington-based Centre for Strategic & International Studies said.

European leaders showed a cautiously receptive ear to President Emmanuel Macron's proposal to debate extending the French nuclear umbrella to Europe on Thursday, though some were reluctant to draw a line under years of U.

With the U.S. showing signs of retreating from its traditional security role, Macron has intensified efforts to strengthen European defense, including proposals to expand Frances

With U.S. security commitments in question, discussions grow around France’s nuclear deterrence strategy for the continent.