Original Constitution
Amendment XX, section 2.
Why? They didn’t need an amendment. The constitution already allowed a provision for them to make a law changing the day the meet. Was it some sort of compromise to get the 20th amendment passed?
Maybe because the amendment specifies the time of day, whereas the original only specified the day. Just a guess, though.
My guess is that it’s to prevent requiring lame duck sessions. New Congress probably starts January 1.
It changes the default, in case they don’t pass a law. Sometimes laws don’t get passed because of inertia, or deadlock, or just because, and you want a sensible default as a backstop.
The previous default of “first Monday in December” was klutzy enough under the old system, when terms ran March 4 through March 4. It would have been totally klutzy under the new (post-XX amendment) system, when terms ran January 3 through January 3. Nobody wants a klutzy default.
That makes sense. Thank you 