diff --git a/src/runtime2/consensus.rs b/src/runtime2/consensus.rs
index daea21188bf15d535f184b8faa1c08a3af865ae8..951045671b8adc3c3eb5901f27538ad6d3c881a7 100644
--- a/src/runtime2/consensus.rs
+++ b/src/runtime2/consensus.rs
@@ -144,6 +144,25 @@ impl Consensus {
         self.branch_markers.push(new_branch_id);
     }
 
+    /// Notifies the consensus algorithm that a particular branch has
+    /// encountered an unrecoverable error. If the return value is `false`, then
+    /// the caller can enter a "normal" exit mode instead of the special "sync"
+    /// exit mode.
+    pub fn notify_of_fatal_branch(&mut self, failed_branch_id: BranchId) -> bool {
+        debug_assert!(self.is_in_sync());
+
+        // Check for trivial case, where branch has not yet communicated within
+        // the consensus algorithm
+        let branch = &self.branch_annotations[failed_branch_id.index as usize];
+        if branch.port_mapping.iter().all(|v| v.registered_id.is_none()) {
+            return false;
+        }
+
+        // Branch has communicated. Since we need to discover the entire
+
+        return true;
+    }
+
     /// Notifies the consensus algorithm that a branch has reached the end of
     /// the sync block. A final check for consistency will be performed that the
     /// caller has to handle. Note that