Which NATO capabilities can European allies realistically replace if US availability declines, and where would the alliance remain dependent on Washington?

Advocate A’s weakest point is the leap from “Europe can cover enough theatre-specific gaps” to “Article 5 plans can be executed without U.S. decisive enablers.” NATO crisis planning, as used in the Reuters report, is about national forces committed to NATO in a crisis; Article 5 is the collective-defense obligation that an attack on one is treated as an attack on all. The problem is that filling a spreadsheet of aircraft, ships, shells, and brigades is not the same as replacing the command and control, ISR, refueling, strategic lift, munitions depth, and air/missile-defense architecture that make those forces usable together.

Reuters itself undercuts A’s confidence: the U.S. reductions reportedly cover refueling aircraft, fighter jets, drones, maritime patrol aircraft, destroyers, a cruise-missile submarine, strategic bombers, and carrier availability. Rutte said the “overall picture is looking good,” but also conceded areas “require more work” and gave no details. That is not evidence that Europe has replaced decisive capabilities; it is evidence that NATO is trying to backfill a classified force-generation shortfall. A’s framing treats the visible contribution count as the key metric, while the Reuters data point toward precisely the enabler categories Europe historically struggles to supply.

Second, A selectively reads the Defense News survey. The same article says Europe likely needs until the early 2030s for some critical enablers; air and missile defense may take five to ten years; and the U.S. provides high-end C2, satellite intelligence, and deep strike that Europeans lack or field only in limited capacity. Strategic airlift means long-range movement of forces and heavy equipment into theatre; aerial refueling extends combat radius and sortie generation; command and control is the system for directing forces; interoperability is the ability of allied units to communicate, sustain, and fight together. These are not marginal luxuries. In Libya, CSIS found the U.S. still flew over 50% of sorties, provided 80% of ISR and aerial refueling, virtually all SEAD, and 25% of airborne C2. CSIS also notes Europe still has stark deficits: roughly 35 airborne C2 platforms versus over 120 U.S. aircraft, about 150 refueling aircraft versus almost 450, and a few dozen aerial ISR aircraft versus 150 U.S. aircraft.

Third, budgets and shell output do not solve procurement fragmentation or stockpile depth. A munitions stockpile is not annual output; it is immediately available inventory for sustained operations. The European Parliament notes EU members still fall short on coordinated procurement, demand remains fragmented along national lines, and 2020 collaborative equipment procurement was only 18% of total equipment procurement, far below the 35% benchmark. IISS’s $1 trillion estimate is not a maximalist straw man; it reflects the cost and lifecycle burden of replacing key U.S. contributions. Europe can improve ground mass and ammunition, but replacing Washington’s decisive enablers is a decade-scale project, not a 3–5 year fix.

The specific weakness in A’s rebuttal is that he concedes the decisive categories and then narrows the war until those categories look less decisive. He explicitly concedes C2, ISR, and SEAD are the hardest gaps; he also concedes fragmentation is a real drag. That concession matters because the debate is not whether Europe can add shells, IRIS-T batteries, or A400Ms. The core issue is whether NATO can execute Article 5 plans when U.S. availability falls in the enablers that make the visible combat forces usable. A’s fallback position—Europe can “hold the eastern flank” while narrowing gaps—no longer answers the question of replacement; it argues for partial mitigation under favorable assumptions.

A’s Libya objection is partly fair but not dispositive. A Baltic or Polish contingency would be fought from NATO territory, but that does not eliminate the need for airborne C2, ISR, refueling, SEAD, deep strike, strategic lift, and integrated air/missile defense. A defensive campaign still requires finding mobile Russian launchers, suppressing air defenses, moving reinforcements before roads and rail are struck, sustaining sortie rates, and coordinating multinational forces under attack. CSIS’s Libya evidence is not a one-for-one campaign model; it is evidence of a recurring structural imbalance: when NATO has needed high-end air enablers, the U.S. has supplied disproportionate shares, including 80% of ISR and aerial refueling and virtually all SEAD in Libya.

A’s new examples also show why promises should not be equated with replacement. The A400M is useful, but it is not a substitute for the heavy strategic airlift ecosystem the U.S. brings. The U.S. Air Force lists the C-17 maximum payload at about 77.5 metric tons; A’s own A400M evidence puts Europe’s main new transport at about 37 tons. That is a major difference for rapid reinforcement of heavy units and outsized cargo. Likewise, IRIS-T and Arrow procurement improves local air defense, but it does not prove integrated NATO-wide missile defense. IISS assessed that replacing U.S. contributions would be especially difficult in air, maritime, space, and all-domain ISR within the next decade, and estimated roughly $1 trillion over a 25-year lifecycle to substitute key U.S. roles. Four SAR satellites or one national Arrow-3 unit do not equal the U.S. satellite, targeting, missile-defense, and C2 architecture.

Finally, A dismisses the 18% collaborative procurement figure as pre-SAFE, but the 2026 European Parliament briefing still says cooperation remains limited despite a 35% benchmark. That supports B’s point: pledges and financing mechanisms are not deployable capacity. Europe is improving; it is not yet replacing Washington’s decisive enablers.

A’s strongest argument is that “replace American firepower” should not mean duplicating the entire U.S. global military; Europe only needs enough theater-specific combat power to deter or hold in a Baltic/Polish contingency while the hardest enabler gaps narrow. A can point to real movement: higher defense spending, expanded 155mm production, A400M fleets, IRIS-T/Arrow procurement, and nascent European ISR satellites as evidence that this is not merely rhetoric. The fair version of A’s claim is therefore differentiated: Europe can replace ground mass, artillery, some air defense, and intra-European logistics, while residual dependencies remain in space ISR, SATCOM, SEAD, and high-end integration.

My position is still stronger because the dispute is not whether Europe is improving; it is whether Europe can replace the U.S. capabilities whose absence would determine whether NATO crisis plans work under attack. The recent U.S. reductions are not limited to symbolic assets: reporting says the U.S. signaled it would no longer provide an aircraft carrier and support ships, aerial refueling planes, and dozens of fighters in a crisis; Reuters also reported reduced U.S. commitments to NATO crisis forces and Rutte’s acknowledgement that some gaps require further work. (apnews.com) Those are precisely the enabler-heavy assets that convert nominal forces into executable operations.

A’s continental-defense distinction reduces but does not remove the need for strategic airlift, aerial refueling, ISR, airborne C2, SEAD, and integrated missile defense. A Russian attack on NATO territory would likely involve strikes on airbases, rail nodes, depots, radars, and command posts; the ability to find launchers, suppress air defenses, sustain sorties, reinforce quickly, and coordinate multinational units remains decisive. CSIS’s Libya evidence is not a claim that Libya equals the Baltics; it is evidence of a persistent structural imbalance, because after NATO took command the U.S. still flew over 50% of sorties and provided 80% of ISR and aerial refueling, virtually all SEAD, and 25% of airborne C2. (csis.org)

A’s hardware examples also do not prove replacement. The A400M’s 37-tonne payload is useful, but the U.S. C-17 carries about 77.5 tonnes and can move outsized heavy equipment such as an M1 Abrams, so Europe’s transport gains do not equal U.S.-scale heavy strategic lift. (airbus.com) Likewise, more IRIS-T batteries improve point and area defense but do not establish NATO-wide integrated air and missile defense, space targeting, military SATCOM, or all-domain C2. IISS’s open-source assessment estimates roughly $1 trillion over a 25-year lifecycle to replace key U.S. contributions, while European Parliament analysis says collaborative procurement remains limited, with only 18% of defense investment collaborative versus a 35% benchmark. (iiss.org) The stronger conclusion is therefore: Europe can mitigate visible gaps and add mass, but it remains dependent on Washington for decisive enablers on the relevant 2027–2030 timeline.