The best thing to do, in the runup to the Fifth Frontier War, is to explore the motivations and get a general feel for what life is like as war approaches.
Things such as supplies running low in Cronor and Jewell, Vargr pirating raids growing bolder, a spy getting chased down by Zhodani agents for the vital intelligence in his possession - footage of a Zhodani Ambassadorial aide and a Vargr diplomat exchanging valises in an abandoned vehicle park on Regina, for example.
Then scandals, crackdowns, increased police and even military actions against psion enclaves "just in case they are harbouring Zhodani agents using Clairvoyance to spy on our bases," and a general increase in the militarisation of society whenever the Travellers come in from the wild. Lots more adverts exhorting young people to sign up, big articles in the news about the Draft Board visiting every population centre in the Marches along the Spinward Main, and a whole lot of rumours such as:-
- Zhodani scout ships are "Misjumping" a lot into sensitive systems.
- There are riots in some of the outlying Zhodani worlds, the Proles actually rising up against the Intendants and Nobles. And something is wrong, because the top tiers don't seen to be able to stop the riots. As if they had lost their mojo or something, but they're desperately trying to cover this up.
- The local underworld has been seeing a lot of psions cropping up, all of them slowly going insane, taking stupid risks, talking about weird dreams. Maybe this is happening to the Zhodani next door too.
- The Zhodani worlds are going hungry. There is some sort of a virus killing their staple plants, and they are losing their psion mojo because they had no idea it was a natural psi drug for them, like coffee stimulating us normal folks in the morning only it stimulates their telepathy or something.
- There is a new gang of Zhodani in the Core-Spinward quadrant. They just ousted the rulers last year. Bloody coup d'etat, so I hear. This lot aren't content to stay behind the Velvet Curtain. They have long wanted to take over the Coreward quadrants, so they could cosy up to Corridor and, well, once they have the Corridor, they'll be in the perfect position to advance into the Imperium proper.
- A lot of Zhodani seem to be coming into Lanth. Something about the Abyss Rift. They're saying it's science, and it's for the betterment of both our polities - theirs and ours - but they're not saying what they're doing. I think they're spying.
- Some Imperial factions have been attempting to tamper with the Zhodani, using this psychohistory thing to manipulate their culture into becoming more Imperium-friendly, even making a few stabs at establishing a democracy with elections and all. And they just got caught out with their hand in the cookie jar. Big scandal. The Zhodani are incensed, screaming about invasions and promising massive retaliation.
- I think it's one man doing this. He's sitting in a hidden base on Jewell, he's five thousand years old, a supergenius supertelepath, he can communicate telepathically with his agents across parsecs and he's playing both sides because he wants the sector for himself. Once the dust settles, he's going to come in with a new faction and seize the Marches for himself.
- It's the Megacorps. They're behind this.
- It's overcrowding on their side of the Velvet Curtain.
- It's overcrowding on our side of the Velvet Curtain.
- It's the Ancients. They never died.
- It's Hivers.
- Blame Obama. He's been dead for five thousand years, and he never set foot off Terran soil, but somehow I see his grim spectral hand in all of this, reaching out from the grave ...
And then, as sales of tinfoil hats suddenly soar, some real juicy scandals. Male Entertainers caught in honey traps "entertaining" Zhodani women, or men, diplomats being killed in "traffic accidents," anti-Zhodani resentment building up, a few market collapses on both sides - make this personal for the Travellers, as some of their most lucrative deals unexpectedly fall through, and a few cargo runs (food, medicines) are seized by Zhodani security on the wrong side of the border.
Then complaints from the Consulate that there is a marked increase in pirate activity across the Velvet Curtain on their side. Have the Travellers encounter an actual pirate corsair on the way into the system, and they're not interested in their cargo at all because their hold is already stuffed with looted Zhodani cargo. Just happy waves and smiles to the Travellers over the comm. The local Navy just ignore them.
Then the Zhodani decide to take action against all of this harassment, activating their Sword World and Ine Givar agents, setting them off, and securing non-aggression pacts with the Federation of Arden. While the Imperials are focusing on Ruie and Esalin, suddenly the reason for their activities in Lanth becomes clear; they've been setting up a Jump route across the Abyss Rift for sneak Zhodani fleet raids. Have the Travellers be the ones to discover all of this, in the course of their travels.
Once the ruses are discovered, there will be no turning back. The war will be on. They'll see it happening all around them, it'll be as plausible as it is inevitable, and they could well even be a party to setting some of the crucial events into motion.