diff --git a/pymodmilter/actions.py b/pymodmilter/actions.py
index c9a1119..0c06bf8 100644
--- a/pymodmilter/actions.py
+++ b/pymodmilter/actions.py
@@ -60,10 +60,10 @@ def add_header(field, value, milter, idx=-1, pretend=False,
 def mod_header(field, value, milter, search=None, pretend=False,
                logger=logging.getLogger(__name__)):
     """Change the value of a mail header field."""
-    if not isinstance(field, re.Pattern):
+    if isinstance(field, str):
         field = re.compile(field, re.IGNORECASE)
 
-    if search is not None and not isinstance(search, re.Pattern):
+    if isinstance(search, str):
         search = re.compile(search, re.MULTILINE + re.DOTALL + re.IGNORECASE)
 
     occ = defaultdict(int)
@@ -110,10 +110,10 @@ def mod_header(field, value, milter, search=None, pretend=False,
 def del_header(field, milter, value=None, pretend=False,
                logger=logging.getLogger(__name__)):
     """Delete a mail header field."""
-    if not isinstance(field, re.Pattern):
+    if isinstance(field, str):
         field = re.compile(field, re.IGNORECASE)
 
-    if value is not None and not isinstance(value, re.Pattern):
+    if isinstance(value, str):
         value = re.compile(value, re.MULTILINE + re.DOTALL + re.IGNORECASE)
 
     idx = -1
diff --git a/pymodmilter/run.py b/pymodmilter/run.py
index d5a3666..686fa69 100644
--- a/pymodmilter/run.py
+++ b/pymodmilter/run.py
@@ -105,12 +105,12 @@ def main():
         if "global" not in config:
             config["global"] = {}
 
-        if "loglevel" not in config["global"]:
-            config["global"]["loglevel"] = "info"
 
         if args.debug:
             loglevel = logging.DEBUG
         else:
+            if "loglevel" not in config["global"]:
+                config["global"]["loglevel"] = "info"
             loglevel = loglevels[config["global"]["loglevel"]]
 
         logger.setLevel(loglevel)
@@ -249,7 +249,7 @@ def main():
 
     logger.info("pymodmilter starting")
     ModifyMilter.set_rules(rules)
-    ModifyMilter.set_loglevel(loglevels[config["global"]["loglevel"]])
+    ModifyMilter.set_loglevel(loglevel)
 
     # register milter factory class
     Milter.factory = ModifyMilter