I hate to say it, and it's way too risky to be adopted as a strategy, but if the WORST were to happen, and they got their ban, there may be a silver lining.
There would then be an opportunity to get a SCOTUS ruling, once and for all, that civilian (semi-auto) versions of standard military small arms are protected, due to their direct relationship to militia use. Wouldn't THAT be nice?
I am unaware of any other scenario that would set up a SCOTUS case so directly.
Believe me, I don't wish for it, because it could be disaster. But Heller could have been a disaster, too.