Well, this certainly isn't a message

More expensive than a stamp, but maybe more effective:

U.S. Successfully Completes Missile Test

VANDENBERG AIR FORCE BASE, Calif. (AP) -- The Air Force successfully launched an unarmed intercontinental ballistic missile early Thursday.

The Minuteman III dummy warheads were fired at 3:14 a.m. and traveled about 4,200 miles before hitting a water target in the Marshall Islands.

"Dear North Korea. Just a reminder that we have nuclear weapons, too, and ours already fly far enough to land in your backyard. Love, Uncle Sam.”