diff --git a/youtube_dl/extractor/senateisvp.py b/youtube_dl/extractor/senateisvp.py
index 387a4f7f6..db5ef8b57 100644
--- a/youtube_dl/extractor/senateisvp.py
+++ b/youtube_dl/extractor/senateisvp.py
@@ -89,7 +89,7 @@ class SenateISVPIE(InfoExtractor):
     @staticmethod
     def _search_iframe_url(webpage):
         mobj = re.search(
-            r"<iframe[^>]+src=['\"](?P<url>http://www\.senate\.gov/isvp/?\?[^'\"]+)['\"]",
+            r"<iframe[^>]+src=['\"](?P<url>https?://www\.senate\.gov/isvp/?\?[^'\"]+)['\"]",
             webpage)
         if mobj:
             return mobj.group('url')