About Doctrine

Doctrine is a geopolitical simulation spanning 1990 to 2050. Take charge of a major or minor power; navigate post-Cold-War alliances, manage economic and military doctrine, and respond to procedurally generated crises. Aerobiz-style decisions on a real d3-geo world map.

How to play

Annual turns from 1990 to 2050 (61 turns). Each year: review intelligence, set foreign-policy posture, allocate military and economic budgets, respond to crises. Non-deterministic events (recessions, civil wars, climate shocks) inject realism. Win condition is open — accumulate national capability score across the full campaign.

Frequently asked questions

How the model works

Doctrine is built by engineers, and the whole campaign is a deterministic turn loop wrapped around a handful of transparent equations. It runs annual turns from 1990 to 2050 inclusive — 61 turns. Each time you end a year the engine resolves rivals, events, and the economy in a fixed order, then advances the clock and checks win/lose conditions. Nothing is hidden dice-rolling behind the scenes; every number below comes straight from the simulation source.

The annual turn cycle

Ending a year runs six steps in sequence: (1) each AI rival spends its tempo on instruments, (2) scripted and random events fire, (3) the economy ticks for all four powers and all twelve middle powers, (4) influence scores are recomputed, (5) the year advances, and (6) win/lose conditions are tested. Tempo — action points per turn — then resets (USA/China/Russia get 3, the fragmented EU gets 2).

The economy model

Growth is recomputed fresh every year from a persistent base rate, so budget dials never ratchet the growth number cumulatively toward its clamp. For each power the effective growth is:

growth = baseGrowth + (infra − 4)×0.5 − max(0, mil − 6)×0.3 − max(0, rate − 6)×0.2 − max(0, debt/GDP − 1.0)×1.5, plus ±1 of noise, clamped to the range −8% … +12%.

GDP then compounds by that growth. Infrastructure spending above 4% of GDP lifts growth; military spending above 6%, interest rates above 6%, and a debt overhang above 100% of GDP all drag it down. Each year the budget is then balanced against revenue:

Debt/GDP is clamped to 0–500%. Military capability eases 15% of the way toward a target set by your military budget each year (clamped 5–200). Approval drifts on growth, social spending, high rates, and debt overhang. Interest rates are a dial you set — there is no automatic central-bank feedback, an honest simplification the dev notes flag as under-tuned.

Alignment and diplomacy

Each middle power holds an alignment score (0–100) toward every bloc. Instruments push those scores with a fixed swing on use and a slow yearly drift while the presence remains:

One-shot costs are financed by issuing debt. Intel operations resolve stochastically: a 60% success chance for the full swing, a 15% chance of blowback (−10), and a 25% chance of nothing. A Defense Pact requires alignment ≥55, then locks that country under a floor and pulls it into your security umbrella. Alignment is effectively zero-sum above saturation: when a country's total alignment across all four blocs would exceed 100, the excess is drained proportionally from rivals — but never below any rival's own pact floor.

Scoring

Influence for a power is computed as the GDP-weighted sum of everyone it has drawn toward it, plus a modest premium on its own hard power:

score = Σ (alignment ÷ 100 × country GDP) + own GDP × 0.5 + own military × 5

Because middle-power GDP dominates that sum, coalition-building among the twelve contested states outscores raw domestic size — the dev notes acknowledge own-military barely moves the needle here.

Events and win/lose

History is layered on in two ways. Eight scripted events fire on their real years — Gulf War (1991), USSR dissolution (1992), Asian financial crisis (1997), 9/11 (2001), the 2008 GFC, Arab Spring (2011), a Crimea-style annexation window (2014, gated on Russian military strength), and the 2020 pandemic. On top of that, random events (Hormuz closure, Taiwan crisis, tech breakthrough, climate disaster, coup, oil spike) draw from a weighted pool with a two-year cooldown and roughly a 45% chance each eligible year, each gated behind a minimum year. The campaign ends with a debt crisis (debt/GDP > 250% and rates > 12%), losing office (approval < 20% for three straight years), hegemony (≥80% of weighted global alignment held for five straight years), or — reaching 2050 — the highest influence score.

Where the model is stylized

Doctrine is a playable model, not a forecasting tool. Tax is a flat share of GDP rather than a real fiscal code; interest rates have no inflation feedback; rival AI is a single greedy heuristic that chases the highest-GDP, lowest-alignment target it can afford; listed alliances (NATO, CSTO) are flavor that grants no mechanical bonus; and chokepoint closures apply GDP shocks without physically blocking deployments. Event probabilities are tuned for replayability over historical fidelity. The starting numbers, though, are grounded in real 1990 data (Maddison-style GDP, SIPRI-style military expenditure).

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