When I see something like "a referendum to overturn a law repealing a ban on X" and get confused, one thing I do is count the negations. In my example there are three, so people who support the referendum are against X and vice versa. Even if there are nuances that simple negation-counting misses (like "always fails to verb" vs. "doesn't always verb successfully", which both have one), that gives me a basic framework that then lets me add the nuances back in without getting confused.