diff --git a/script.js b/script.js
index 51ce9ac..2dad4bc 100644
--- a/script.js
+++ b/script.js
@@ -1747,6 +1747,9 @@ class Simulation {
       founded: this.year,
       legitimacy: this.rng.range(0.68, 0.94),
       cohesion: this.rng.range(0.58, 0.9),
+      charisma: this.rng.range(0.5, 1.5),
+      leaderStarted: this.year,
+      leaderTenureYears: this.rng.range(24, 68),
       crisis: 0,
       lastCrisisYear: this.year
     };
@@ -1811,6 +1814,45 @@ class Simulation {
     for (const polity of this.polities) this.samplePolityHistory(polity);
   }
 
+  selectNewLeader(polity, forced = false) {
+    if (!polity) return;
+    const previousCharisma = clamp(polity.charisma ?? 1, 0.5, 1.5);
+    const center = this.getCityById(polity.centerCityId);
+    const centerStability = center ? clamp(center.loyalty ?? 0.5, 0, 1) : 0.5;
+    const institutionalBias = ((polity.legitimacy ?? 0.7) + (polity.cohesion ?? 0.6) + centerStability) / 3;
+    const randomLeader = this.rng.range(0.5, 1.5);
+    const continuity = forced ? 0.18 : 0.34;
+    const institutionalPull = 0.82 + institutionalBias * 0.36;
+    const nextCharisma = clamp(
+      previousCharisma * continuity + randomLeader * (1 - continuity) * institutionalPull,
+      0.5,
+      1.5
+    );
+    polity.charisma = nextCharisma;
+    polity.leaderStarted = this.year;
+    polity.leaderTenureYears = this.rng.range(22, 72);
+
+    const change = nextCharisma - previousCharisma;
+    polity.legitimacy = clamp((polity.legitimacy ?? 0.7) + change * 0.08 - (forced ? 0.035 : 0), 0, 1);
+    polity.cohesion = clamp((polity.cohesion ?? 0.6) + change * 0.045 - (forced ? 0.020 : 0), 0, 1);
+    if (forced) polity.crisis = clamp((polity.crisis || 0) + 0.04, 0, 1.5);
+  }
+
+  updatePolityLeaders() {
+    for (const polity of this.polities) {
+      polity.charisma = clamp(polity.charisma ?? 1, 0.5, 1.5);
+      polity.leaderStarted ??= polity.founded ?? this.year;
+      polity.leaderTenureYears ??= this.rng.range(24, 68);
+      const tenureYears = (this.year - polity.leaderStarted) / MONTHS_PER_YEAR;
+      const oldLeader = Math.max(0, tenureYears - polity.leaderTenureYears);
+      const crisisPressure = clamp((polity.crisis || 0) * 0.045, 0, 0.09);
+      const successionChance = clamp(oldLeader * 0.018 + crisisPressure, 0, 0.36);
+      if (successionChance > 0 && this.rng.next() < successionChance) {
+        this.selectNewLeader(polity, (polity.crisis || 0) > 0.85);
+      }
+    }
+  }
+
   markPolityEnded(polity, reason = "dissolved") {
     if (!polity) return;
     const history = this.ensurePolityHistory(polity);
@@ -1916,7 +1958,7 @@ class Simulation {
     const instability = this.polityInstability ? this.polityInstability(polity) : 0;
     const agePressure = this.polityAgePressure ? this.polityAgePressure(polity) : 0;
 
-    return Math.max(0,
+    const basePower = Math.max(0,
       Math.sqrt(population) * 1.35 +
       Math.sqrt(treasury) * 1.15 +
       avgLoyalty * 16 +
@@ -1924,6 +1966,7 @@ class Simulation {
       instability * 12 -
       agePressure * 6
     );
+    return basePower * clamp(polity.charisma ?? 1, 0.5, 1.5);
   }
 
   polityInfluenceRange(polity, wartime = false) {
@@ -2656,6 +2699,7 @@ class Simulation {
     if (this.erodePolityLegitimacy) this.erodePolityLegitimacy();
     if (this.triggerPolityCrises) this.triggerPolityCrises();
     if (this.applyOldStateStress) this.applyOldStateStress();
+    if (this.updatePolityLeaders) this.updatePolityLeaders();
 
     this.updateCityLoyalty();
     this.absorbIndependentCities();
@@ -3059,6 +3103,9 @@ class Simulation {
         founded: p.founded,
         legitimacy: p.legitimacy,
         cohesion: p.cohesion,
+        charisma: p.charisma,
+        leaderStarted: p.leaderStarted,
+        leaderTenureYears: p.leaderTenureYears,
         crisis: p.crisis,
         lastCrisisYear: p.lastCrisisYear
       })),
@@ -3145,6 +3192,9 @@ class Simulation {
       founded: p.founded || 0,
       legitimacy: p.legitimacy ?? 0.7,
       cohesion: p.cohesion ?? 0.6,
+      charisma: clamp(p.charisma ?? 1, 0.5, 1.5),
+      leaderStarted: p.leaderStarted ?? p.founded ?? sim.year,
+      leaderTenureYears: clamp(p.leaderTenureYears ?? 48, 12, 96),
       crisis: p.crisis ?? 0,
       lastCrisisYear: p.lastCrisisYear ?? sim.year
     }));
@@ -3439,6 +3489,8 @@ function renderTooltip() {
     ${cityEthnicity ? `<span><b>City majority</b><em>E${cityEthnicity}</em></span>` : ""}
     ${city ? `<span><b>State</b><em>${polity ? `#${polity.id}` : "Independent"}</em></span>` : ""}
     ${city ? `<span><b>Loyalty</b><em>${city.loyalty.toFixed(2)}</em></span>` : ""}
+    ${polity ? `<span><b>Charisma</b><em>${clamp(polity.charisma ?? 1, 0.5, 1.5).toFixed(2)}</em></span>` : ""}
+    ${polity ? `<span><b>Leader tenure</b><em>${Math.floor((sim.year - (polity.leaderStarted ?? polity.founded ?? sim.year)) / MONTHS_PER_YEAR)}y</em></span>` : ""}
     ${polity ? `<span><b>Treasury</b><em>${polity.treasury.toFixed(1)}</em></span>` : ""}
     ${polity ? `<span><b>Center</b><em>${polity.centerCityId === city.id ? "yes" : "no"}</em></span>` : ""}
     ${agent ? `<span><b>Ethnicity</b><em>E${agent.ethnicity}</em></span>` : ""}