diff --git a/programs/conditional_vault/src/instructions/merge_tokens.rs b/programs/conditional_vault/src/instructions/merge_tokens.rs
index 6a9ff848..54a514e6 100644
--- a/programs/conditional_vault/src/instructions/merge_tokens.rs
+++ b/programs/conditional_vault/src/instructions/merge_tokens.rs
@@ -1,6 +1,15 @@
 use super::*;
 
 impl<'info, 'c: 'info> InteractWithVault<'info> {
+    pub fn validate_merge_tokens(&self) -> Result<()> {
+        require!(
+            !self.question.is_resolved(),
+            VaultError::QuestionAlreadyResolved
+        );
+
+        Ok(())
+    }
+
     pub fn handle_merge_tokens(ctx: Context<'_, '_, 'c, 'info, Self>, amount: u64) -> Result<()> {
         let accs = &ctx.accounts;
 
diff --git a/programs/conditional_vault/src/instructions/split_tokens.rs b/programs/conditional_vault/src/instructions/split_tokens.rs
index 4213d88f..e8937774 100644
--- a/programs/conditional_vault/src/instructions/split_tokens.rs
+++ b/programs/conditional_vault/src/instructions/split_tokens.rs
@@ -1,6 +1,15 @@
 use super::*;
 
 impl<'info, 'c: 'info> InteractWithVault<'info> {
+    pub fn validate_split_tokens(&self) -> Result<()> {
+        require!(
+            !self.question.is_resolved(),
+            VaultError::QuestionAlreadyResolved
+        );
+
+        Ok(())
+    }
+
     pub fn handle_split_tokens(ctx: Context<'_, '_, 'c, 'info, Self>, amount: u64) -> Result<()> {
         let accs = &ctx.accounts;
 
diff --git a/programs/conditional_vault/src/lib.rs b/programs/conditional_vault/src/lib.rs
index 4568f3e7..9dfa1400 100644
--- a/programs/conditional_vault/src/lib.rs
+++ b/programs/conditional_vault/src/lib.rs
@@ -59,6 +59,7 @@ pub mod conditional_vault {
         InitializeConditionalVault::handle(ctx)
     }
 
+    #[access_control(ctx.accounts.validate_split_tokens())]
     pub fn split_tokens<'c: 'info, 'info>(
         ctx: Context<'_, '_, 'c, 'info, InteractWithVault<'info>>,
         amount: u64,
@@ -66,6 +67,7 @@ pub mod conditional_vault {
         InteractWithVault::handle_split_tokens(ctx, amount)
     }
 
+    #[access_control(ctx.accounts.validate_merge_tokens())]
     pub fn merge_tokens<'c: 'info, 'info>(
         ctx: Context<'_, '_, 'c, 'info, InteractWithVault<'info>>,
         amount: u64,