Nutshell: Excellent. A gripping tale of paranoia making the best use of the Dominion yet.
Now I'm impressed. Not only has Deep Space Nine managed to get through the first leg of the season without a loser episode, it continues to show more promise with its arc development. "Homefront" is both a strong character story and a plausible intrigue outing. It's the best episode since "The Visitor," and considering how good the season has been, that is saying quite a bit.
A Changeling spy bombs a conference on Earth, killing 27 people—an act of murder of such magnitude which the planet hasn't experienced in over a century. As a result, Admiral Leyton of Starfleet Command (Robert Foxworth), Sisko's mentor and commanding officer from his days serving on the USS Okinawa, calls Sisko to Earth and appoints him Acting Head of Earth Security so he can oversee the implementation of security procedures which have proven effective in detecting Changelings on DS9. Odo comes along as the expert on shapeshifters. Hoping for some family time while on Earth, Sisko brings along Jake, and the two stay with Ben's father, Joseph Sisko (Brock Peters).
Sisko's security procedures are a start, but do not prove entirely effective against the craftier of shapeshifters; within days of the new system coming on line, a Changeling spy is still able to trespass on Starfleet Headquarters grounds, masquerade as Admiral Leyton, and easily escape. The new security measures are still not sound, however, President of the Federation Jaresh-Inyo (Herschel Sparber) will only allow so much in terms of security. He cannot justify anything more extreme. Earth is paradise, and he does not want to jeopardize paradise by turning it into a military organization where civilians are forced to submit to blood screenings.
There's a very effective scene where Sisko convinces the President how serious the Dominion threat really is by walking into his office with a briefcase for a meeting. The briefcase is really Odo, who morphs into his humanoid form much to the President's surprise. I'm amazed I didn't identify the briefcase as Odo right away, but the scene does such a good job of sidetracking us that it's as much of a surprise to us as to the President.
"Homefront," however, is not just another Dominion intrigue story like "The Adversary." This episode is about people, and how being in constant fear of an invisible invasion affects their lives. Earth is supposed to be paradise, but it never feels like it in this episode. Everybody is scared and paranoid. Tensions haven't been as high on the planet since the Borg incident. Present here, which wasn't in "Adversary," is a very strong character undercurrent. The episode's best scenes are those between Ben and his father. Early scenes do a wonderful job of establishing Joseph and his famous New Orleans' restaurant. The restaurant is a convincing set with pleasing details that go a long way in establishing a welcome, homey tone in spite of Earth's present crisis. Brock Peters turns in an impressive portrayal of the stubborn, elderly Sisko, whose health problems have both his son and grandson getting on his case to take better care of himself. The writers are very accurate in their portrayal of Joseph being old and inflexible. When Ben asks him why he never visits Deep Space Nine, Joseph replies "Who would run the restaurant?" Anyone with elderly relatives has heard this line before. At the same time, Peters seems perfectly cast as Ben's father; there's an aura of natural charisma between him and Avery Brooks.
Later in the episode, the tone becomes dramatically charged when Starfleet security officers try to take blood samples from Joseph, under Ben's own new security condition requiring relatives of all high ranking officers to be blood-screened for Changeling infiltration. Joseph adamantly refuses on principle, telling Ben that he never took an oath to Starfleet, and despite Earth's current paranoia, he'll be damned if he's going to adhere to ridiculous security measures and live his life in fear. Ben just wishes his father would cooperate for once, instead of being so obstinate. This is a powerful scene—well acted by both Brooks and Peters—and it feels genuinely accurate because the crisis situation fits together in a plausible manner with relevant day-to-day human issues. Distracted by the argument, Joseph cuts himself while chopping vegetables, and suddenly Ben finds himself uncontrollably staring at the blood, almost expecting it to reveal Changeling properties. It does not, and Joseph is appalled—his own son thought he was a shapeshifter.
This highlights the episode's theme, which at the moment is probably the most relevant theme in the series. To quote Odo's very precise words, "That's why my people came here; to undermine the trust and mutual understanding the Federation is built on." The funny thing about this whole scene is that I was actually half-expecting Joseph's blood to morph into Changeling liquid. "Homefront" allows us to truly understand Ben's fear and paranoia, because it has a way of making the threat seem extremely real. This is very, very well done. I haven't felt this engrossed in a Star Trek threat since TNG's "Best of Both Worlds."
The last two acts step away from this theme somewhat in order to continue developing a plot to leave us hanging until part two. Suddenly, there's a massive power outage (the entire planet, if you can swallow that), knocking out the entire planetary defense network and leaving Earth defenseless. Suspecting this sabotage is the first step of a Dominion strike, Sisko and Leyton ask the President to declare a state of emergency—something that, aside from the Borg emergency, hasn't happened in over 100 years. This way they can put armed officers on the streets to resist a possible Jem'Hadar invasion force.
President Jaresh-Inyo is reluctant to do this—he doesn't want to be remembered as the president who put arms on every street of Planet Paradise—but he ultimately agrees. There is no other option. If the Dominion attack without encountering some sort of resistance, Paradise will be more than lost—it will be destroyed.