First of all, if the mail is first class, priority, express or anything "service requested," then getting refused mail returned to them is part of the original postal paid. Meaning a sender incurs no charge if the mail piece gets returned to them as refused or any other kind of undeliverable status.
Second, most political ad mail isn't first class mail, but 3rd class. I'm relatively sure this is what you got. If you as the addressee refuse it, it doesn't go back to the sender. Instead, it goes only to your local post office, and the clerks there will send it to whatever recycling service the local USPS uses, along with all the other undeliverable junk mail that came back to them.
There's only one time when a sender will have to pay for mail returned to them, and that's if they didn't put enough postage on the mail the first time around. The USPS is nice enough to send it back and ask for the sender to affix the rest of the necessary amount--no need to re-stamp it or re-meter it. Just add 3 cents or whatever postage.
So all you're doing there is costing the postal service money, no one else.
And before you go there, yes, I'm an idiot about most things, but I do know what I'm talking about with this one thing.
Signed,
A former USPS clerk who had multiple positions within the returned mail/mail forwarding process. I think I covered them all over the years I worked there.
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