diff --git a/game/README.md b/game/README.md
index 4311bf4..7901ffb 100644
--- a/game/README.md
+++ b/game/README.md
@@ -102,9 +102,13 @@ remove-and-banish flow.
   non-empty and must match an existing race in the engine's roster.
 - Successful response: `204 No Content` with an empty body.
 - Error responses follow the same `400` / `500` envelope shape as the
-  other admin endpoints. The engine-side mechanics of `banish` (what
-  exactly happens to the race's planets, fleets, and pending orders) are
-  owned by the engine maintainers.
+  other admin endpoints. `banish` only flags the race extinct, so it can
+  no longer submit or have orders applied; its assets are released at the
+  start of the next turn generation (`TurnWipeExtinctRaces`), the same way
+  an idle/quit timeout is handled but without the wait — ship groups and
+  fleets are removed, its planets become uninhabited (the working industry
+  and the capital stockpile are cleared, raw material is retained), and
+  votes cast for it are reset.
 
 ### `GET /healthz`
 
diff --git a/game/internal/controller/race.go b/game/internal/controller/race.go
index c4d35c1..b48d5bd 100644
--- a/game/internal/controller/race.go
+++ b/game/internal/controller/race.go
@@ -117,13 +117,34 @@ func (c *Cache) raceTechLevel(ri int, t game.Tech, v float64) {
 }
 
 func (c *Cache) TurnWipeExtinctRaces() {
-	for i := range c.listRaceActingIdx() {
-		if (c.g.Race[i].Extinct && c.g.Race[i].TTL > 0) || (!c.g.Race[i].Extinct && c.g.Race[i].TTL == 0) {
+	for i := range c.listRaceIdx() {
+		r := &c.g.Race[i]
+		// Idle timeout or voluntary quit: a still-active race whose TTL ran
+		// out. Administrative banish: a race already flagged extinct that
+		// still holds assets to release. Once a race is wiped it owns nothing,
+		// so the asset check keeps this idempotent across later turns.
+		if (!r.Extinct && r.TTL == 0) || (r.Extinct && c.raceHasAssets(i)) {
 			c.wipeRace(i)
 		}
 	}
 }
 
+// raceHasAssets reports whether the race still owns a planet or a ship group.
+func (c *Cache) raceHasAssets(ri int) bool {
+	id := c.g.Race[ri].ID
+	for i := range c.g.Map.Planet {
+		if c.g.Map.Planet[i].OwnedBy(id) {
+			return true
+		}
+	}
+	for i := range c.g.ShipGroups {
+		if c.g.ShipGroups[i].OwnerID == id {
+			return true
+		}
+	}
+	return false
+}
+
 func (c *Cache) wipeRace(ri int) {
 	c.validateRaceIndex(ri)
 	r := &c.g.Race[ri]
diff --git a/game/internal/controller/race_test.go b/game/internal/controller/race_test.go
index 043ac1b..84c6409 100644
--- a/game/internal/controller/race_test.go
+++ b/game/internal/controller/race_test.go
@@ -1,6 +1,7 @@
 package controller_test
 
 import (
+	"slices"
 	"testing"
 
 	e "galaxy/error"
@@ -90,3 +91,39 @@ func TestRaceID(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, Race_0_ID, id)
 }
+
+// TestBanishReleasesAssets checks that an administratively banished race only
+// gets flagged extinct, and its planets and ships are released during turn
+// generation; a second pass is a no-op.
+func TestBanishReleasesAssets(t *testing.T) {
+	c, g := newCache()
+	c.CreateShipsUnsafe_T(Race_1_idx, c.MustShipClass(Race_1_idx, Race_1_Gunship).ID, R1_Planet_1_num, 3)
+	assert.True(t, c.MustPlanet(R1_Planet_1_num).OwnedBy(Race_1_ID))
+	assert.Len(t, slices.Collect(c.RaceShipGroups(Race_1_idx)), 1)
+
+	assert.NoError(t, g.RaceBanish(Race_1.Name))
+	assert.True(t, c.Race(Race_1_idx).Extinct)
+	assert.True(t, c.MustPlanet(R1_Planet_1_num).OwnedBy(Race_1_ID), "still owned until the turn runs")
+
+	c.TurnWipeExtinctRaces()
+	assert.False(t, c.MustPlanet(R1_Planet_1_num).Owned())
+	assert.Len(t, slices.Collect(c.RaceShipGroups(Race_1_idx)), 0)
+
+	// Idempotent: re-running over an already-wiped (asset-less) race is a no-op.
+	c.TurnWipeExtinctRaces()
+	assert.False(t, c.MustPlanet(R1_Planet_1_num).Owned())
+}
+
+// TestIdleRaceWipedOnTimeout guards that a still-active race whose TTL ran out
+// (idle timeout or quit) is still wiped after the iterator change.
+func TestIdleRaceWipedOnTimeout(t *testing.T) {
+	c, _ := newCache()
+	c.CreateShipsUnsafe_T(Race_1_idx, c.MustShipClass(Race_1_idx, Race_1_Gunship).ID, R1_Planet_1_num, 1)
+	c.Race(Race_1_idx).TTL = 0
+	assert.False(t, c.Race(Race_1_idx).Extinct)
+
+	c.TurnWipeExtinctRaces()
+	assert.True(t, c.Race(Race_1_idx).Extinct)
+	assert.False(t, c.MustPlanet(R1_Planet_1_num).Owned())
+	assert.Len(t, slices.Collect(c.RaceShipGroups(Race_1_idx)), 0)
+}