As for the law, IANAL, but I’ll copy and paste the legal link, adding emphasis:
[The following stuff is not mailable, meaning you shouldn’t send things like this:]
[INDENT]INDENT Matter otherwise legally acceptable in the mails which—
(1)** is in the form of, and reasonably could be interpreted or construed as, a bill, **invoice, or statement of account due; but
(2) constitutes, in fact, a solicitation for the order by the addressee of goods or services, or both;
is nonmailable matter, shall not be carried or delivered by mail, and shall be disposed of as the Postal Service directs, unless such matter bears on its face, in conspicuous and legible type in contrast by typography, layout, or color with other printing on its face, in accordance with regulations which the Postal Service shall prescribe—
(A) the following notice: “This is a solicitation for the order of goods or services, or both, and not a bill, invoice, or statement of account due. You are under no obligation to make any payments on account of this offer unless you accept this offer.”; or
(B) in lieu thereof, a notice to the same effect in words which the Postal Service may prescribe.
[/INDENT][/INDENT] I can’t tell from the images whether the RNC included the above notice or words to the effect that the Postal Service may prescribe.
Either way it’s pretty sleazy. At any rate, I say that the law should be enforced. No special privileges for the RNC.