The arc since 1945—how U.S. military power enabled dominance

• Security architecture: The U.S. built and underwrote the post-WWII alliance web (NATO in 1949; later bilateral pacts in Asia). Permanent forward posture—hundreds of overseas sites—let Washington deter adversaries, reassure allies, and move forces quickly. Estimates hover around ~750 overseas sites in ~80 countries, an unmatched footprint. 

• Scale and tech edge: America has long outspent everyone—$997B in 2024 (~40% of global)—backing a nuclear triad, carrier groups, stealth, precision strike, ISR, cyber, and now space. That budgetary dominance translated into rapid power projection and influence over global security rules (sea lanes, no-fly zones, counter-terror ops). 

• Cold War → unipolar moment: Containment succeeded; the USSR collapsed. Through the 1990s–2000s, the U.S. waged coalition wars (Gulf War, Balkans, Afghanistan, Iraq) and policed chokepoints and shipping lanes, reinforcing the credibility of U.S. guarantees and the broader U.S.-led order. (Alliance spending data underscore that centrality: in 2023 NATO accounted for ~55% of world military outlays.) 

What’s changed—where dominance is under challenge

1. Great-power military catch-up (especially China).

   • Capacity: The PLA Navy is on track to be the world’s largest by hull count (CRS projects ~395 ships by 2025, ~435 by 2030), backed by expanding missile, space, and cyber forces, and growing budgets.

   • A2/AD & tech: Rapid advances in long-range anti-ship, hypersonics, drones, and EW aim to push U.S. forces back in the Western Pacific. Beijing’s 2024 DoD-tracked developments and 2025 parade plans highlight that anti-access focus.

   • War-driven rearmament and contested regions.

   • Russia’s full-scale invasion of Ukraine reignited high-intensity conventional conflict; Moscow lifted spending to an estimated $149B in 2024 (~7.1% of GDP). That strains U.S./allied stockpiles and industry and keeps Europe’s security unsettled. 

2. Alliance math is evolving.

   • The burden is spreading: 22 of 32 NATO members hit 2% of GDP in 2024, and allies are debating a new 5% “defence & resilience” target (3.5% core defence + 1.5% wider security). If realized, Europe and the Pacific allies would field more mass and munitions, but the bar is politically and fiscally steep. 

3. Industrial base & adaptation pressures.

   • The character of war (cheap loitering munitions, counter-drone, deep magazines, resilient C2, and space assets) is shifting faster than traditional acquisition. Keeping carrier air wings, submarines, and air dominance platforms lethal—while producing vast stocks of affordable missiles and drones—tests U.S. timelines and budgets. (SIPRI’s 2024–25 data show the fastest global spending jump since the Cold War’s end, and competitors are buying, too.) 

So—does the U.S. still dominate?

• Yes, but it’s now contested dominance: The U.S. retains the world’s most capable joint force, global basing, unmatched lift and logistics, a diversified nuclear triad, and deep alliance networks—backed by the largest defence budget. Those are durable advantages. 

• Where the edge is narrowing: In the Western Pacific inside the first and second island chains; in munitions depth and shipbuilding throughput; and across tech races (hypersonics, counter-C4ISR, autonomous swarms) where diffusion is fast and costs favor the challenger. 

What to watch (litmus tests for the next 3–5 years)

• Allied spending translation to capability (air defense layers, ISR, magazines, shipyards), not just meeting a % target.

• U.S. industrial surge (submarines, air- and sea-launched missiles, drone mass) versus adversaries’ production ramps. Western Pacific crisis management: Can AUKUS/Quad coordination plus posture in Japan/Philippines deter fait-accompli moves around Taiwan and the South China Sea as PLA capacity grows? 

Bottom line: U.S. military power has been the backbone of its global dominance since 1945 by underwriting alliances, deterring rivals, and projecting force worldwide. That dominance persists—but it’s shifting from uncontested to competitive, especially in Asia, as rivals expand forces and technology and as the cost of staying ahead rises sharply. The outcome will hinge on how quickly the U.S. and its allies convert higher spending into resilient, modernized combat power and deeper magazines.

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U.S. can keep underwriting global security, but not as a solo “policeman.” It’s shifting to coalition sheriff + system architect—still first among equals, yet more dependent on allies and industrial depth than at any time since 1945.

What “sustainability” really means

1) Resources & industry.

• Money isn’t the binding constraint: U.S. defense outlays were about $850–$895B for FY2025; worldwide military spend hit $2.7T in 2024, with the U.S. near $1T—~40% of the global total. 

• The pinch is industrial capacity (subs, ships, missiles, and shells). The Navy’s 30-year plan aspires to ~381 battle-force ships but faces delays and yard constraints; CBO and CRS flag the gap, while Washington is even courting Korean/Japanese shipbuilding help to fill naval support needs. 

• Munitions: the Army aimed for 100k 155mm shells/month in 2025 but has hovered around ~40k/month; new plants (e.g., Iowa “Future Artillery Complex”) are being stood up to raise output. 

2) People.

• Recruiting stress is easing from a deep dip (the Army had major shortfalls two years ago), with 2025 showing momentum and new tactics (e.g., influencer campaigns). But the ten-year trend in entry-level enlistees is still down. 

3) Legitimacy & politics.

• At home, most Americans still favor a leading/major role globally (≈66%). Abroad, views are mixed: in many countries the U.S. is the top ally, yet in others it’s seen as a top threat—which complicates “policing” without partners.

4) Allies as force multipliers.

• NATO’s burden-sharing is finally moving: 23 allies met 2% of GDP in 2024, with talk of a new 3.5% core-defense target by 2035. Reality check: moving from ~2.2% average to 3.5% is a heavy lift; follow-through matters. 

• In the Indo-Pacific, AUKUS (subs, tech) and tighter posture with Japan/Australia/Philippines help sustain deterrence, but U.S./allied submarine and shipbuilding bottlenecks could stretch timelines. 

The verdict

• Unipolar “global cop,” everywhere, all the time? No—industrial, manpower, and legitimacy constraints make that model brittle.

• Coalition-based enforcer of key rules (maritime lanes, nuclear deterrence, denial of faits accomplis in Europe and the Western Pacific)? Yes—if the U.S. leads a thicker coalition and fixes production bottlenecks.

Practical playbook (next 3–5 years)

1. Pick the beats, not every beat: Prioritize the Western Pacific and Europe; accept risk elsewhere. (Budget is large; magazines and yards aren’t.) 

2. Industrial surge for the “cheap and many”: Scale shells, SAMs, anti-ship and land-attack missiles, and autonomous systems—where capacity, not just dollars, is short. Track monthly 155mm output as a KPI. 

3. Maritime logistics & repair network: Fast-track auxiliary fleets and Indo-Pacific repair options via Japan/Korea partnerships to keep ships on station. 

4. Allies to capability, not just percentages: Hold NATO to converting higher spend into air defense layers, ISR, and munitions stockpiles; treat AUKUS timelines and submarine yard throughput as critical path. 

5. Recruiting & retention modernization: Build on 2025 gains; expand lateral entries, technical tracks, and reserve/industry integration. 

Bottom line: America can keep being the backbone of global security—but only by leading coalitions, rebuilding industrial depth, and focusing on priority theaters. The age of the lone “world’s policeman” is over; the age of the coalition sheriff is here.