The Broadsword spacelane

The ambitiously named Broadsword spacelane was established early on in the "Scramble for New Alderamin" by Revanchist colonizers.  From the corner of the Revanchist Republic, it pushes through the Dhangetan Cartel to the Carthen Colony—a real coup that the Republic was able to switch those systems from red to blue; they had once been part of the Carrick Grand Marches.  From there, it makes one more stop through a Dhangetan system, an independent system, and hits the Calder Settlements.  The former spacelane continued into Calder and Altairan systems that have since been conquered and established as part of Outremer Umbral Crusader states.  This has "broken" the spacelane, although some people do, in fact, continue to use it.  It is largely closed off, however, to official Republic convoys, especially military ones, at least at the "southwestern" edge.

As the Republic continues to push, however, it's also managed to damage relationships with the Dhangetans.  This spacelane has evolved into one that neither corporate nor military Revanchists can expect to use without trouble, but any independent operator, or small trader can still follow the entire route without any issue.  The Seraeans are only too happy to tariff traders passing through from Calder to the Belebach worlds (which used to be part of the Calder Settlements in happier days.)

When passing through the Dhangetan systems, it's worth pointing out that the majority of the people you have to deal with when stopping for refueling are not, of course, Dhangetans, who rule as extremely rare individuals.  Humans, oerks, cetians, Sirians, and especially skiffers are the people you most deal with, and they tend not to care as much about politics.

Even passing through the Vichy worlds of Outremer, you will often deal with lingering officials of Altairan or even Revanchist extraction who have not (yet) been replaced by Seraeans or their allies, because they're simply aren't enough of them to worry about manning the docks of the spaceports.  Some of those who make this run are little more than privateers, who in fact prey on Imperial transport, so some of these stops are fraught with some danger if their ships are recognized.

Some of them are trying to reroute the lane somewhat, but there aren't any safe harbors that get to the Belebach worlds and the republican allies without going through the Emerus Marches—which is nearly as intolerable to Revanchists as dealing with the Imperials.