diff --git a/src/whiteboard/action.hpp b/src/whiteboard/action.hpp
index 5dd94ad0229..fb921aff1d7 100644
--- a/src/whiteboard/action.hpp
+++ b/src/whiteboard/action.hpp
@@ -81,7 +81,7 @@ public:
 	 * display (and avoid any change to the game state) accordingly
 	 */
 	virtual void set_valid(bool valid) = 0;
-	virtual bool is_valid() = 0;
+	virtual bool is_valid() const = 0;
 
 	/** Constructs and returns a config object representing this object. */
 	virtual config to_config() const;
diff --git a/src/whiteboard/move.hpp b/src/whiteboard/move.hpp
index aa7d21daf30..24ad3fb31e9 100644
--- a/src/whiteboard/move.hpp
+++ b/src/whiteboard/move.hpp
@@ -76,7 +76,7 @@ public:
 	virtual map_location get_numbering_hex() const;
 
 	virtual void set_valid(bool valid);
-	virtual bool is_valid() { return valid_; }
+	virtual bool is_valid() const { return valid_; }
 
 	virtual config to_config() const;
 
diff --git a/src/whiteboard/recall.hpp b/src/whiteboard/recall.hpp
index e6f1f97817f..9dc62fa3ca2 100644
--- a/src/whiteboard/recall.hpp
+++ b/src/whiteboard/recall.hpp
@@ -66,7 +66,7 @@ public:
 	 * display (and avoid any change to the game state) accordingly
 	 */
 	virtual void set_valid(bool valid) { valid_ = valid; }
-	virtual bool is_valid() { return valid_; }
+	virtual bool is_valid() const { return valid_; }
 
 	virtual config to_config() const;
 
diff --git a/src/whiteboard/recruit.hpp b/src/whiteboard/recruit.hpp
index f9d3ad82ef9..2683ebc3c71 100644
--- a/src/whiteboard/recruit.hpp
+++ b/src/whiteboard/recruit.hpp
@@ -70,7 +70,7 @@ public:
 	 * display (and avoid any change to the game state) accordingly
 	 */
 	virtual void set_valid(bool valid) { valid_ = valid; }
-	virtual bool is_valid() { return valid_; }
+	virtual bool is_valid() const { return valid_; }
 
 	virtual config to_config() const;
 
diff --git a/src/whiteboard/suppose_dead.hpp b/src/whiteboard/suppose_dead.hpp
index 8a174f7f345..708d420c367 100644
--- a/src/whiteboard/suppose_dead.hpp
+++ b/src/whiteboard/suppose_dead.hpp
@@ -65,7 +65,7 @@ namespace wb {
 			virtual map_location get_numbering_hex() const { return loc_; }
 
 			virtual void set_valid(bool valid);
-			virtual bool is_valid() { return valid_; }
+			virtual bool is_valid() const { return valid_; }
 
 			virtual config to_config() const;
 	//	}	End Inherits from action