Time Travel Causality (#SFWApro)

The ability to cheat cause-and-effect is one of the things time-travel movies have to work around if they’re to work at all.
Consider Scarlet O’Hara. Much of Gone With the Wind is fueled by the fallout from Ashley Wilkes proposing to Melanie, then marrying her. Scarlet constantly schemes to win Ashley’s heart but the one thing she can’t do is change what’s happened. He’s fallen for Melanie, all her plans have to deal with that.
Give Scarlet a time machine (and once GWTW is out of copyright, I wouldn’t be surprised) and all bets are off. She can go back, try to change what happened, try to become the woman Ashley wants—which frankly I don’t think has a chance in hell of working, but I’m sure she’d give it a shot.
Time travel lets you cheat causality. It lets you not live with the consequences of your action. If your do-over doesn’t work out, you can try again, or undo your do-over. This, of course, can easily get out of hand, because if there are no consequences to someone’s actions, there’s no drama. So time travel films have multiple solutions:
•The one-shot deal. Peggy Sue in Peggy Sue Got Married and the protagonist of Before You Say ‘I Do’ get a chance to change their pasts, but it’s a one-shot deal. They’ve been magically dropped into an earlier time, if they can’t rewrite history then too bad, so sad.
•Practical obstacles. Time machines get stolen. Or break.
•Bad consequences. This is the Monkey’s Paw school of time-travel, where everything goes horribly wrong unless you either stop or put it back the way it was (case in point, The Butterfly Effect).
•Emotional decisions. At a key point in Minutemen, the protagonist plans to go back and undo the moment when he rescued a kid from bullies, because going up against the cool kids permanently ruined his social life. Then the kid he rescued, who’s been his best buddy ever since, reveals how much it meant to him to have a friend … and so the protagonist lets history unroll as it always did. Likewise the lead of Always Will wipes out his entire awesome do-over life so that his mother will end up happy (because by negating his power to do-over, he also eliminates the event that brought her together with his abusive stepfather).
•Loss of control. Groundhog Day movies (Groundhog Day, 12:01, Christmas Do Over, Last Day of Summer) are completely causality free: Nothing the protagonist does makes any difference to the next day. Bill Murray in Groundhog Day commits suicide, smokes, eats insanely unhealthy meals because he knows he’s trouble free. In a Groundhog Day episode of Stargate: SG-1, Jack O’Neal (Richard Dean Anderson) suddenly kisses Col. Carter (Amanda Tapping) because he knows she’ll forget so no consequences.
But the catch, of course, is that whatever or whoever is pulling the strings, it isn’t the protagonist. Freedom from causality is a trap, a time treadmill that keeps you running through the same temporal loop over and over. Victory is getting causality back, not escaping it.
I’ll see if I think of more methods as the book goes along.