As confidence in Washington’s long-term role in NATO weakens, Paris is seeking to place France at the centre of Europe’s defence adaptation. But nuclear status and strategic ambition do not by themselves provide the troops, industry, logistics and political continuity needed to replace American power.

Emmanuel Macron has long argued that Europe cannot base its security on the assumption that the United States will always treat European interests as its own. That argument, once dismissed by many NATO allies as a French preoccupation, has moved closer to the centre of European strategic debate as Washington’s role becomes less predictable.

The issue is not simply whether the United States remains inside NATO. It is whether Europe can still rely on the full American security system that has underpinned the alliance for decades: intelligence, command structures, strategic airlift, missile defence, satellite communications, refuelling, logistics and political authority. A reduction in any of these areas would alter Europe’s defence calculations.

France is the European Union state best placed to lead part of that adjustment. It is the EU’s only nuclear power, has a significant defence industrial base, maintains expeditionary military experience and retains a strategic culture shaped by the belief that alliances are useful, but dependence is dangerous. That outlook has deep roots, including the 1956 Suez crisis, when France and Britain were forced by Washington to end their intervention in Egypt.

Yet France cannot replace the United States. It lacks American scale, force enablers and logistics depth. Its role would not be to become a European Washington, but to push Europe towards a more coherent military and political posture.

The scale of the problem is considerable. According to estimates by Bruegel and the Kiel Institute, Europe would need about 300,000 additional troops and around €250 billion more in annual defence spending to deter Russia without effective US support in the short term. That would mean the equivalent of roughly 50 new brigades. But numbers alone do not capture the gap. Europe’s weakness lies less in the absence of soldiers on paper than in its limited ability to move, command, sustain and integrate forces rapidly.

Ukraine is the immediate test. Financially, Europe has shown that it can shoulder a large part of the burden. Militarily, replacing American support is far harder. The United States remains central to supplies of several categories of heavy weapons, long-range precision systems, air defence and ammunition. European industry produces artillery, armoured vehicles, air defence systems and combat aircraft, but not yet at the speed or volume required to make strategic autonomy more than a political formula.

The limits of European defence co-operation are visible in the Future Combat Air System, launched by France and Germany in 2017 as a flagship project for European strategic autonomy. It has been slowed by disputes over industrial leadership, design control and diverging requirements. France needs an aircraft compatible with its nuclear deterrent and carrier operations. Germany has different priorities and has ordered American F-35s, reducing urgency around a future European system.

France’s nuclear posture is another element in Macron’s attempt to give Europe a stronger strategic centre. In March 2026, he used a speech at Île Longue to call for French deterrence to be considered in the depth of the European continent. France has signalled greater consultation, possible temporary deployments of nuclear-capable Rafale aircraft among allies, and more co-ordination on early warning, air defence and long-range strike capabilities. But Macron has not offered a NATO-style nuclear-sharing arrangement. As the Egmont Institute has noted, France is discussing a wider European role for its deterrent, not shared control over it.

That distinction matters. French nuclear weapons may strengthen Europe’s political deterrent, but they cannot compensate for shortfalls in conventional forces. If Europe cannot prevent Russia from gaining early military advantage on the ground, no doctrinal adjustment in Paris will solve the problem. Europe still needs brigades, ammunition, mobility, command structures and industrial capacity.

The political context is shifting as well. NATO’s next summit, scheduled for Ankara on July 7-8, 2026, will take place amid unresolved questions over the alliance’s future structure, internal cohesion, burden-sharing, support for Ukraine, deterrence policy, and the strategic consequences of any further reduction in US engagement.

France’s own politics add another uncertainty. Macron’s current line assumes that Paris will continue to support a wider European role in deterrence, Ukraine policy and defence integration. That cannot be taken for granted. The National Rally has been more cautious on Ukraine and less committed to Macron’s European defence agenda. Marine Le Pen has opposed opening France’s nuclear doctrine to a wider European dimension and has threatened withdrawal from NATO’s integrated command structures.

France therefore remains necessary but insufficient. It has the strategic culture, nuclear capability and political ambition to act as the centre of gravity for a more European security order. But it lacks the mass to replace the United States, and its present course may not survive domestic political change.

The question is not whether Paris can build a “new NATO” in Europe. It is whether France can help Europe reduce dependence on Washington quickly enough to deter Russia, sustain Ukraine and prevent the gap between American retrenchment and European readiness from widening.