The more letters you send out begging for money, the less I'm inclined to give you. If it was a really time-limited thing -- as in, the whole shebang would be over and done with in one month -- okay, you've only got so much time. But the political circus is NEVER over. Once a week, okay. Once a month, better. Once a day? Twice a day? New deadlines every week that OMG MUST MEET OR THE RACE IS LOST? No. I lose interest completely. One letter a year, that would be ideal. Remind me of the cause, let me know what the situation is, and let me decide if and when I want to donate.
But the more stridently you tell me how DOOOMED things are EVERY SINGLE DAY? Sorry, the less I believe you, and the less I care. It becomes very much like telemarketers, and they shut me off automatically when they call; it now no longer matters to me if a telemarketer's for a political party I hate, or for the Police Benevolent Association, if the phone call's clearly robo-dialed, I hang up. It's over.
You want to convince me to care? Act as though you care about my time and attention and not like you must scream about DOOOOM every ten seconds.