Wolf.
Henny Penny
I think the dog should be an ENEMY dog, against which we should be alert and vigilant. I picture a checked cloth wrapped around the head. And a female companion villain with a veil.
Maybe the government could do a deal with the tobacco industry turn Joe Camel into the symbol of America’s enemies. Or maybe, Joe Camel Jockey. 
Terrell the Terrorist Terrier?
Aren’t the schools still using McGruff? Won’t another dog confuse kids?
How many of these jokes are going to be used (stolen? :eek: ) by the late night talk shows? There’s at least a month’s worth here for Leno.
This is a gold mine; not that I can think of any …
Hey! I resemble that remark! 
(Snipe, in addition to being a ficticious prey for hunting, is also a nickname for engineers in the Navy.)
[quote]
Seven: Wolf.
Oh. I love it!
Bruno
if it must be a hero dog, it should be Mr. Phelps.
Y’know, it took me ages to get Warren Terrier. I’d be embarrassed, but I’m giggling too much.
Ok. I have it…
Mr. Phelps, the terror-fighting dog (a border collie – a reference to homeland security).
Akbar the Afghan hound, the evil master criminal dog.
Irina, the veiled Persian cat femme fatale.
I see a series of ads. Each one has a different racial flavor of an American family in a single family home. Outside is a really BIG yard shaped exactly like the continental United States. And right along the edge patrols Mr. Phelps, barking at the smugglers, terrorists, pimps and ho’s all trying to get in. The family breathes a joint sight of relief for their guard dog, and puts some burgers on the grill.
And a series of cartoon shorts, kinda like the Warner Brothers ones of the wolf trying to get at the flock of sheep but the guard dog pulverizing the wolf every time.
And there can be some allies… Ali, the (Saudi) Arabian Horse… Tony the British poodle… ok, make him a bulldog for politeness sake.
At the risk of accusations of being an unimaginative, Onion-copying bastard…
And at the risk of accusations of juvenile Nazi comparisons and Godwinizing…
I’m going to suggest “Kampfy the Überhund.”
Yes.
'Fraidy Cat
I second Seven’s nomination of “Wolf”. Sure, it’s a dog, but when you see it, you cry “Wolf!”
Fluffy.
Be funnier if his name was “Fido.” 
Spot. See Spot run. Run Spot, run!
What’s way funnier than the name is the debate over the breed.
Last week on NPR they did a story about the whole mascot thing, and the subject of breed came up. The BushCo PR person was quick to point out that the dog is an “American Shepherd.” But the reporter could find no kennel organization that registers “American Shepherds”… there’s the North American Shepherd, but it is the same breed as the Miniature Australian Shepherd, or, more accurately there was a big argument between breeders over which name is correct… to the point where the breed association just punted and now calls them North American Miniature Australian Shepherds…
But there is still no such thing as an “American Shepherd.” Yet the Homeland Security PR flak they had on the phone swore up and down “someone told her” that it is indeed a real breed…
It’s Freedom Fries all over again, but this time with dogs.
There is an “American White Shepherd,” which may have the perfect image for the Mascot job, but it’s just a white german shepherd. The American White Shepherd Association likes to claim it’s a standard breed, but they’re just a club of folks who have white german shepherds. I’m sure that if they and the DHS get togther, though, we’re gonna have an official proclamation of a new registered breed faster than you can slap a Bush sticker on a bottle of Heinz ketchup.
I have yet to find an actual image of this proposed mascot that needs a name, so who knows what it actually looks like… perhaps that was intentional of the DHS.
That was my very first thought while reading the OP… “WTF is an American Shepherd?” I would be willing to bet that I’m more familiar with the truly rare and esoteric breeds than most, and I’ve got a healthy familiarity with the “breed” names people give randomly bred dogs to market something they’re not, but even so, American Shepherd is a new one on me.