Schneier on Security

#4, Kurushio is my vote, based on "what I think is the appropriate".

looking back at what the Stated Goals and definitions from Wikipedia, though, points another direction.

You asked for: "a better logo and a snappy motto. ...
Rules are simple: create a TSA logo. "

Wikipedia says:
"Logo is a term used to refer to a graphic mark or emblem commonly employed by commercial enterprises, organizations and even individuals to aid and promote instant public recognition."

However it is worth noting that Wikipedia also says:
"The logo (ideogram), is the image embodying an organization. Because logos are meant to represent companies' brands or corporate identities and foster their immediate customer recognition, it is counterproductive to frequently redesign logos."

Obviously, though, this contest was aimed at "subvertising",
Wikipedia Again:
"The wide recognition received by the most famous logos provides the brand's critics with the possibility of meme-hacking, a process also known as subvertising, turning the marketing message carried by the logo (either in its pristine form, or subtly altered) into a vehicle for an alternative message, frequently highly critical to the brand in question."

So the "Best" subversive logo would be one that looked like the original, but had the best counter-message... I liked #4 for its message, but #3 is MUCH more similar to the original, and also keeps with strong "red white and blue colors", intended to invoke patriotism, means it qualifies better, even though I personally think it is somewhat weak/lame.

Again, count my vote for #4, but I think a better answer yet should still come. Not sure the best advantage to take of the results, though.