diff --git a/src/gamestate.cpp b/src/gamestate.cpp
index ccb7084..a6229fa 100644
--- a/src/gamestate.cpp
+++ b/src/gamestate.cpp
@@ -455,7 +455,7 @@ bool GameState::tryAutoMoveMultipleCards(const QList<PlayingCard*>& cards, int s
     return false;
 }
 
-bool GameState::isFoundationMoveValid(const PlayingCard& cardToMove, int foundationId) {
+bool GameState::isFoundationMoveValid(const PlayingCard& cardToMove, int foundationId) const {
     assert(foundationId >= 0 && foundationId < 4);
     const auto foundationSuit = static_cast<PlayingCard::Suit>(foundationId);
     const auto& foundationStack = m_foundation[foundationId];
@@ -484,7 +484,7 @@ bool GameState::isFoundationMoveValid(const PlayingCard& cardToMove, int foundat
     return cardToMove.value() == requiredValue;
 }
 
-bool GameState::isColumnMoveValid(const PlayingCard& cardToMove, int columnId) {
+bool GameState::isColumnMoveValid(const PlayingCard& cardToMove, int columnId) const {
     assert(columnId >= 0 && columnId < 7);
     const auto& columnStack = m_columns[columnId];
 
diff --git a/src/gamestate.h b/src/gamestate.h
index cbeaae7..e44df58 100644
--- a/src/gamestate.h
+++ b/src/gamestate.h
@@ -64,8 +64,8 @@ class GameState : public QObject {
     bool tryAutoMoveSingleCard(PlayingCard& cardToMove, int skipColumnId = -1);
     bool tryAutoMoveMultipleCards(const QList<PlayingCard*>& cards, int skipColumnId);
 
-    bool isFoundationMoveValid(const PlayingCard& cardToMove, int foundationId);
-    bool isColumnMoveValid(const PlayingCard& cardToMove, int columnId);
+    bool isFoundationMoveValid(const PlayingCard& cardToMove, int foundationId) const;
+    bool isColumnMoveValid(const PlayingCard& cardToMove, int columnId) const;
 
     void ensureColumnRevealed(int columnId);
 };