I'm surprised nobody's mentioned the one obvious analogy to the plot of this episode (well, it was immediately obvious to me, anyway, and also to my oldest son, who watched it from halfway across the country, so I can site two separate sources): September 11th.
To me, this episode simply
screamed 9-11. Here's the Earth, sitting fat, dumb, and happy, when out of the blue comes a major, devastating attack from an unexpected source. Extreme damage is incurred. The reaction is first one of disbelief and shock, followed quickly by anger and a desire for retaliation (especially on the part of Trip, who lost someone close to him in the attack).
I don't wish to start a political discussion about the terrorist attacks of 9-11, but this episode (to me, at least) seems a sort of parallel and possible catharsis to the 9-11 attacks. In real life, the US suffered an unexpected attack, found out who was responsible, and was eager to punish those who engineered the carnage. We're still eager to do so, but Al-Qaeda and Osama bin Laden are apparently still around. On
Enterprise, we see a similar situation occurring (on a much bigger scale: 7 million people dead as a result of the Xindi attack), and we see Archer and crew heading off to go do something about it. Since this is a TV show, we're pretty certain that, even though it might take the better part of a season, we'll get to see the good guys triumphant in the end.
Now, this might all just be in my head, but I have to wonder if these parallels were intentional. My guess: yep.
Hopefully, I haven't crossed any "political discussion" lines by bringing this up. If so, I'll bear the moderators no ill will if they want to edit this post to oblivion. (I'll just pretend it was hit by one of those new-fangled photonic torpedoes.)
Johnathan