diff --git a/cli/src/commands/operation/diff.rs b/cli/src/commands/operation/diff.rs
index 596cbc6e2..461db2593 100644
--- a/cli/src/commands/operation/diff.rs
+++ b/cli/src/commands/operation/diff.rs
@@ -40,7 +40,6 @@ use crate::cli_util::short_change_hash;
 use crate::cli_util::short_operation_hash;
 use crate::cli_util::CommandHelper;
 use crate::cli_util::LogContentFormat;
-use crate::command_error::user_error;
 use crate::command_error::CommandError;
 use crate::diff_util::DiffFormatArgs;
 use crate::diff_util::DiffRenderer;
@@ -93,9 +92,6 @@ pub fn cmd_op_diff(
     } else {
         to_op = workspace_command.resolve_single_op(args.operation.as_deref().unwrap_or("@"))?;
         let to_op_parents: Vec<_> = to_op.parents().try_collect()?;
-        if to_op_parents.is_empty() {
-            return Err(user_error("Cannot diff operation with no parents"));
-        }
         from_op = repo_loader.merge_operations(command.settings(), to_op_parents, None)?;
     }
     let graph_style = GraphStyle::from_settings(command.settings())?;
diff --git a/cli/src/commands/operation/show.rs b/cli/src/commands/operation/show.rs
index c494099c6..70ca646f6 100644
--- a/cli/src/commands/operation/show.rs
+++ b/cli/src/commands/operation/show.rs
@@ -17,7 +17,6 @@ use itertools::Itertools;
 use super::diff::show_op_diff;
 use crate::cli_util::CommandHelper;
 use crate::cli_util::LogContentFormat;
-use crate::command_error::user_error;
 use crate::command_error::CommandError;
 use crate::diff_util::DiffFormatArgs;
 use crate::graphlog::GraphStyle;
@@ -55,9 +54,6 @@ pub fn cmd_op_show(
     let repo_loader = &repo.loader();
     let op = workspace_command.resolve_single_op(&args.operation)?;
     let parents: Vec<_> = op.parents().try_collect()?;
-    if parents.is_empty() {
-        return Err(user_error("Cannot show the root operation"));
-    }
     let parent_op = repo_loader.merge_operations(command.settings(), parents, None)?;
     let parent_repo = repo_loader.load_at(&parent_op)?;
     let repo = repo_loader.load_at(&op)?;
diff --git a/cli/tests/test_operations.rs b/cli/tests/test_operations.rs
index ad4121421..8935c8dbb 100644
--- a/cli/tests/test_operations.rs
+++ b/cli/tests/test_operations.rs
@@ -1211,9 +1211,9 @@ fn test_op_show() {
     "###);
 
     // The root operation is empty.
-    let stderr = test_env.jj_cmd_failure(&repo_path, &["op", "show", "0000000"]);
-    insta::assert_snapshot!(&stderr, @r###"
-    Error: Cannot show the root operation
+    let stdout = test_env.jj_cmd_success(&repo_path, &["op", "show", "0000000"]);
+    insta::assert_snapshot!(&stdout, @r###"
+    000000000000 root()
     "###);
 
     // Showing the latest operation.
diff --git a/lib/src/repo.rs b/lib/src/repo.rs
index bea1fa8be..037d49c77 100644
--- a/lib/src/repo.rs
+++ b/lib/src/repo.rs
@@ -753,8 +753,8 @@ impl RepoLoader {
         Arc::new(repo)
     }
 
-    /// Merges the given `operations` into a single operation.
-    /// Assumes that there is at least one operation.
+    /// Merges the given `operations` into a single operation. Returns the root
+    /// operation if the `operations` is empty.
     pub fn merge_operations(
         &self,
         settings: &UserSettings,
@@ -763,7 +763,11 @@ impl RepoLoader {
     ) -> Result<Operation, RepoLoaderError> {
         let num_operations = operations.len();
         let mut operations = operations.into_iter();
-        let base_op = operations.next().unwrap();
+        let Some(base_op) = operations.next() else {
+            let id = self.op_store.root_operation_id();
+            let data = self.op_store.read_operation(id)?;
+            return Ok(Operation::new(self.op_store.clone(), id.clone(), data));
+        };
         let final_op = if num_operations > 1 {
             let base_repo = self.load_at(&base_op)?;
             let mut tx = base_repo.start_transaction(settings);
@@ -789,6 +793,7 @@ impl RepoLoader {
         op_heads: Vec<Operation>,
         user_settings: &UserSettings,
     ) -> Result<Operation, RepoLoaderError> {
+        assert!(!op_heads.is_empty());
         self.merge_operations(
             user_settings,
             op_heads,