Simple solution: Create a singularity of extreme, rapidly growing, negative energy value. By exerting force on it, the entity would theologically absorb energy sources in a linear beam, that includes matter. Due to the rapid loss in energy, the gain of energy through mass absorption cannot destroy the entity, thus, such an entity can be manipulated into removing parts of the moon to form the profanity.
In English: Transfer all of the USA's debt into a single point and give it a shove.
Some comic author had the idea in "Z comme Zorglub" ; this character (Zorglub, a genius that was fired from the university because of his crazy ideas) auto-proclaiming itself "the electronic dictator", turning people into loyal zombies with some EM wave. To make his soldiers/scientists/agents/servitors impossible to understand by other people, he learns them (via an electronic processing machine that "format" their brain) to speak backwards. Like "Rocket" becomes "Tekcor".
So to strike the world attention, he launches hundred of rockets towards the Moon, spreading a red chemical paint... But neglected a tiny little detail : the whole operation was in the hand of his zombies... That of course wrote the message backwards So he gets completely depressed and is recovered by the "good ones".
I think a giant laser projection (forgot who said it again) would be the most effective. How's about 1x106 Watts? and green. I think it would definately be visable, but would melt the moon though :/