When you ever hear a liberal say "we don't need the Constitution," it doesn't really matter what came before or comes after that phrase. Just know that they mean it:
The biggest roadblock to liberalism is the US Constitution that was written specifically to restrict a central government. Liberalism has been pissing on that document ever since, washing away the words by redefinition via judicial fiat one character at a time. Why would Obama, or any other Democrat for that reason, agree to put yet another explicit roablock against their communist agenda?