You want do-overs, eh? So do I.
National health insurance / health care.
Every civilized country on this planet, and a few not-so-civilized ones, has proven that the most affordable, most efficacious way to keep their citizens healthy is to spread the costs over the entire population. We've batted this idea around for something like 100 years now, so STFU on market experiments and pass Medicare For All already.
Iraq / Afghanistan.
I used to know some people, but they're dead now. We've got a lot of Christians in this country who think that dead = in a better place, ie Heaven, but color me skeptical on this one. I don't see y'all committing suicide in droves just to get there. I don't see y'all signing up in droves to go off to some desert halfway around the world and let people take potshots at you either.
Repeal The Patriot Act, the Military Commissions Act, the Protect America Act, that stupid bankruptcy law. Have I missed any? Probably.
Hard to undo an election, isn't it? That's why we have impeachment, and you need to use it on both Bush and Cheney. Oh, wait. The only impeachable offense is engaging in sexual shenanigans while being a Democrat. My bad.
You're in a real pickle, aren't you? It's a sorry state of affairs that I have a bunch of Republicans --- the opposition, mind you --- to thank for the opportunity to vote for the last real Democrat left in the race when the ridiculously early Florida primary rolled around.
Your primary process is stupid, as has been pointed out to you since long before January 29, 2008, so don't you dare spend a single one of my few remaining hard-earned, stretched-too-thin-already tax dollars trying to wiggle out from under this train wreck.
I voted already, and you can either count that vote or count me out.