I know it’s not the thrust of your post, but I have to remark briefly on that.
There could not be a national anti-sodomy law, passed by the federal government. Bills passed by Congress have to fall within the powers given them by the Constitution. Everything else is reserved to the states. For example, take the domestic violence act passed by Congress. It really stretched its language, desperately seeking a justification under the commerce clause, but ultimately was deemed unconstitutional for lack of Congressional authority to pass such a bill. Likewise, sodomy laws are traditionally a matter of state law, the federal government has no enumerated power that might allow them to pass a bill pertaining to the issue. (Likewise for gay marriages, the federal government is powerless to intervene either for or against…the Defense of Marriage Act is probably unconstitutional to that extent if it ever were challenged, but since there’s no power behind it there will probably never be a situation in which it needs to be challenged.)
Flag burning may have the same problem, I can’t see under which enumerated power the Congress might find authority to pass a bill concerning the subject. And there are the 1st Amendment issues too. I think it’s pretty clear that sort of bill would have to go through the Amendment process instead.
When it comes to legislation that affects alot of people and makes sweeping changes, that’s gonna come mostly from the states. So politics is local, as we all knew from the get-go.