A blockade sealing the Earth system's tunnel gate, trapping the resistance in orbit and ruining everyone outside it.
An embargo has closed the main tunnel access route into the Earth system. York reports it to Colonel Boomer as the reason the Homecoming Queen cannot leave yet, even though nobody has fired so much as a single missile at them.
On the other side of the gate the effect is total. Zander leased Squirties, a refueling platform just outside the tunnel access route, with his life savings; with the embargo in place nobody is going through the gate, he has not had a refueling customer in days, and even the reporters have stopped coming. Between the embargo, the destruction of a mantis system and the general threat of war, nobody will approach the area at all, and Zander owes Dictum twenty-five thousand credits a month he cannot pay. The blockade meant to contain the crawl's fallout is instead strangling the bystanders and penning the resistance's fleet exactly where it wants to fight.
The blockade shaping the endgame, holding the resistance in Earth orbit and bankrupting the traders outside.