Yeah, but wouldn't it be a bit hard for the Romulans to conduct an invasion if their supply lines had to go through Federation space or all the way around?
Perhaps. But that's also true of the Klingon invasion of Cardassia, and they managed just fine. This despite them being so desperate that, after clearing UFP space and reaching neutral space bordering on Cardassia, they chose a Federation-overseen installation for their final waypoint before launching the attack...
Clearly, supply lines in space warfare are not particularly important: it appears to be something of a standard strategy to send one decisively sized fleet to crush the opponent in one stroke, counting on surprise, overkill and speed.
Alternately, supply lines are easily maintained even across great distances, in fact due to those great distances: it takes major intelligence effort or phenomenal luck to find the enemy's supply ships in the depths of space.
Note the significant reach of the maneuver arrows on the DS9 wall maps. Apparently, borders mean little or nothing in space warfare. Fronts may form, in the sense of there being a defended line of star systems - but that apparently doesn't stop fleets from roaming and raiding.
But that system was still inside Cardassian teritory.
...Thereby upping the ante, because Cardassian territory was essentially hostile to the Obsidian Order enterprise.
Organizing one's forces for attack outside the safety of one's home turf is not particularly rare in Trek. Klingons did it in "Way of the Warrior". Everybody came to Bajor to do it in "In Purgatory's Shadow". The Feds organized impromptu fleets on frontier starbases ("Unification") and in deep space ("Descent"). And the Dominion had a mighty fleet hidden next to the Gamma end of the wormhole, weeks' travel away from actual Dominion space, in "In Purgatory's Shadow".
Apparently, while starships are remarkably self-sufficient war machines, it does pay to do a final regrouping just on the doorstep of the target. If you have cloaks and the enemy doesn't have an exceptionally good intelligence agency, you probably won't be noticed until it's too late. Or then you do want to be noticed, so that the enemy, who's already waiting for the inevitable, now waits for it in a place of your choosing, not his...
So, we know there's something called a Romulan front. You could say it was just a part of the main front that the Romulans took over, but calling it a 'second' front wouldn't make much sense then.
On your first two quotes, this second front would obviously be the one where the Dominion/Cardassian wedge attack is pushing against Romulan space. Formerly, those forces didn't threaten Romulus directly, but merely used that space for backstabbing action. Now, there's open military conflict at that interface - a second front, far removed from original Cardassian space and thus definitely deserving of the name.
On calling this new front "the Cardassian border", Sisko would be factually correct, but (as you say) using the enemy's lingo where he should be sprouting propaganda for the home team. However, the Romulans could have struck targets in old Cardassian space in addition to opening a second front, thereby excusing the third comment.
All of the above is in defense of the
Star Charts interpretation, of course, not an objective analysis of the evidence. But it doesn't sound plausible for me to give Romulus and Cardassia a common border, when the oft-declared writer/art department intent (as translated to the few onscreen maps) was to have Romulans to the right, Cardassians to the left of the UFP. The Romulans were always described as the besieged, from their POV wronged party, incapable of the sort of expansion they'd prefer. The Cardassians in turn were bit players, at one point separated from the UFP by a big swath of neutral space and eventually held behind the DMZ. For these two to form any sort of an astrographical connection, one would have to extend a long pseudopod towards the other - for no good story reason, since all Romulan-Cardassian interaction before the war was described in terms of long distances and unlikely connections.
By that standard we should accept all those background maps that show the Federation spanning a substantial part of the Galaxy, when even at the highest cited figure of 8000 ly it would be much smaller.
Just for the heck of it,
Star Charts actually integrates the perspective map from "Conspiracy" in the Alpha/Beta pages. It just assumes that map was something of a zoom-in, only spanning the area of the Alpha/Beta maps in the book. As for the top view in e.g. "The Emissary" or "The Chase", that doesn't necessarily describe the UFP, as no such labeling is visible. Dr. Galen could well be expected to use a map showing vast old galactic empires when explaining the itinenary of his latest research tour to Picard...
All Trek cartography is guesswork. Yet
Star Charts tries to incorporate at least a little bit of "real" Star Trek into it, including the Probert and Okuda map graphics. Giving up on those would negate the whole purpose of the work.
It is, however, an outdated work. Not only would ENT change some of the facts there, but ST:NEM would give new data on the shape of the RNZ (as depicted on the floor mosaic of the Romulan Senate)... With that zigzag line, it can't easily be interpreted as an eggshell any more.
couldn't you say they were just showing the main front, where a part of Romulan forces was also deployed later in the war to support the Feds/Klingons, with a second, Romulan front also existing?
Quite possibly - and that second front wouldn't have to be anywhere near Romulan space, just like Churchill's second front against Hitler in Africa was nowhere near the British isles, or like his third in Italy still remained distant from his home turf.
However, the maps linger on the walls till the very end of the war, and the Romulan symbol stays where Romulan space in
Star Charts is depicted as being. That sort of dictates the cartography of the war, and imposes limitations on prewar cartography as well. If that's where the Romulans were shown fighting in the war, then a prewar joint border would be unlikely since it should see fighting as well. And Cardassian space in its entirety is depicted in those wall maps, as a solid amber shape surrounded by black space in every direction.
...it's likely many of the races that long ago weren't advanced enough..
I don't really like this argument, because we know of several cultures that were very advanced thousands of centuries before Vulcans got their act together. The galaxy should be constantly populated by advanced cultures - but also constantly populated by mediocre and primitive ones, existing in the lacunae between their betters. Romulans might have stumbled onto a local empty spot. Or they may have stumbled onto the territory of somebody who isn't in the habit of contacting lesser species.
Remember that Earth wasn't contacted either, not by superior snobs like Vulcans, nor by superior conquerors like Klingons, not even by superior opportunists like the Ferengi or, say, the Tellarites. Contact probably just isn't all that common, unless the culture doing the contacting is at the exact right phase of its cultural, industrial and military development.
I don't know this either but some of that might be determined by whether or not the Romulan flight from Vulcan was an organized, one-time mass exodus -- or a less coordinated and incremental event in which the Rommie population on Vulcan slowly dwindled away
Considering that it happened roughly 2,000 years before the shows' present day, it would be perfectly possible to say that history recounts it as a mass exodus - but that this history is largely a fabrication and that the truth was less glorious and featured plenty of small groups and perhaps a little bit of return flow as well...
Timo Saloniemi