diff --git a/lieer/gmailieer.py b/lieer/gmailieer.py
index 8430cfb..88cdec4 100755
--- a/lieer/gmailieer.py
+++ b/lieer/gmailieer.py
@@ -193,6 +193,13 @@ def main(self):
             help="Read recipients from message headers. This is always done by GMail. If this option is not specified, the same addresses (as those in the headers) must be specified as additional arguments.",
         )
 
+        parser_send.add_argument(
+            "--blocking",
+            action=argparse.BooleanOptionalAction,
+            default=True,
+            help="Whether the call should block on other operations on the local repository, or error out. Defaults to blocking.",
+        )
+
         parser_send.add_argument(
             "-f",
             type=str,
@@ -1011,7 +1018,7 @@ def load_resume(self, f, lastid):
             return ResumePull.new(f, lastid)
 
     def send(self, args):
-        self.setup(args, args.dry_run, True, True)
+        self.setup(args, args.dry_run, True, args.blocking)
         self.remote.get_labels()
 
         msg = sys.stdin.buffer.read()