P ARIS—French President Emmanuel Macron is rekindling debate over whether France’s nuclear arsenal should play a role in deterring attacks against European allies, igniting criticism across the political spectrum from lawmakers who say any move to extend the country’s nuclear umbrella risks compromising a linchpin of national sovereignty.

Macron has made it clear that France would consider deploying troops to Ukraine if two specific conditions are met: a breakthrough by Russian forces and an official request from Kyiv. While he has expressed an unwillingness to exclude any options in defending Ukraine,

Europe and the United States have now committed more than £130bn to Ukraine in aid but NATO members have stopped short of promising boots on the