Evidently not.
Since its founding in 2271 there have been numerous conflicts within the state. Some of them open clashes, others more like a cold war. But even when there was no open civil war, I think you (in general, not you personally) can hardly deny that each power bloc within the state was sharpening its knives in expectation of another conflict.
I'd point out that every state in the Inner Sphere has had internal conflicts within that time period. Heck, the Terran Hegemony was formed by a military coup. The FWL continued to get along until outside influences messed with their politics. That isn't an indication that their way of doing things didn't work.
You may have a point when refering to the last civil war. And even in this context it wasn´t so unequivocal, as you describe it. There were, after all, the Blakists installing a puppet regime (Corinne Marik and Paul) by coup. And Thomas "Halas" had just been revealed as impostor. Technically there was no legitimate C-G before the provinces declared their independence.
This is something of a gray area. While Thomas had fled to Oriente and Corrine was queen of the moment the League was still functioning, if only on paper. You may recall that FWLP disbanded by vote well after the 3 main CGs started their bids for power. Heck, when Thomas was expossed he wanted to call FWLP in to vote on the matter. WoB had anticipated a riot. Instead, they had to instigate things by gassing FWLP and the Knights.
If you consider the FWL and the office of CG seperate entities, the League itself, and even the divded FWLM continued to get along, in some cases in palces without being ordered, like Tamarind. This to me indicates that despite a collapse in central leadership or even well functioning legislative process, the military was trying to protect vulnerable League territories at a time when provincial loyalties were all the rage.
As a sidenote: To my knowledge, the actual infighting started with the gas attack on the Knights and Corinne Marik being forced by her Blakist masters to send FWLM units to mop up what was left of the Knights.
You may be confussing things. The 1st Knights were gas bombed. Corrine took leadership in the coup instigated by Paul Marik. The 2nd FWL took up post as Corrine's Praetorians. When Thomas Halas sent the 2nd Knights to Atreus in order to rescue Cheryl Halas, then the Blakists and Corrine-loyal FWLM units chased them down and shelled them to death.
--------
But I´d like to point to the whole 800 years of FWL exitsance. If we hope to find some universally applicable principles, some common denominator that runs through the FWL history, we cannot just look to recent events. And there have been numerous conflicts within the League out of a caleidoscopic multitude of reasons. Some led to open civil war, some not. But the struggle within the state was always a perceivable undercurrent.
That's the story of every state in the Inner Sphere, to some degree. In just the 31st century you have:
-2 Rebellions on Skye
-The St. Ives defection and reclaimation
-The Haseks siding with the Cappies
-The Sondovals launching unauthorized attacks against the DCMS
-Operation Sovergn Justice
-The Ronin War
-The FedCom Civil War
-The Andurien Crisis
-Janos Marik's Rebellion
Clearly, politics as usual in the 31st century were ugly for everyone. Other than the conflicts of the 31st century, the FWL endured the Scourge of Death and the deadlock in FWLP over the Comstar War. What other huge conflicts did the FWL suffer that make it the lame horse?
There have been dynastic struggles, in this you are right. (The Sian-Mariks or even Anton´s revolt)
There have been clashes because of foreign policy. (For instance the Andurien War, who was about attacking the Cappies or not)
There have been struggles between parliament and the C-G. (Like when they cut the funding of successful military operations)
There have been conflicts because of domestic policy. (The virtual SAFE-police state of Gerald and Elise Marik comes to mind)
There have been numerous occasions when the provinces agitated versus the gouverment. (See Home Defense Act)
The only two of these that are unique to the FWL are the Home Defense Act and Parliament denying war funds. No other state would dream of giving their regional militaries a legal opt-out of participation in national defense. Not even the DCMS, which is infamously divided by the loyalties of their Warlords is the same thing as Regulus recalling their forces for an imaginary crisis, or the Anduriens becoming a defacto training cadre with 1 regiment seeing action during the Anton Marik revolt.
Conclusion: There was always bad blood. Noone ever trusted the other. The fracture lines were always there, be it between the different levels of the administration (federal/provincial/planetary) or along cultural lines. (Regulans vs. Mariks, Anduriens vs the rest etc)
One of the things that makes the FWL the FWL, IMO is that they left the welding seems of their foundation. The member states met as equals and stayed nebulous as time went on. Compare this to the Confederation, which over time became more centralized. One of the things that made the FWL fun and unique was that each state was allowed to voice their opposition. If that makes it a noisy, quarrelsome place, so be it. Democracy is messy, even when it is suborned to a defacto dynastic military dictatorship.
I will concede, that "who should be C-G?" seems like the important question, because many of the abovementioned conflicts ended with a different Marik being installed as C-G. (Or not.) But then there were few instances (out of my head I´d say just the Sian-Marik issue) where the personnel matter was the only point of contention.
Usually there was an already existing conflict of interests in general, before one faction presented a counter-candidate. (usually a Marik)
I guess my position is "meh". I prefer the original idea behind the Captian-General, the Warden-General appointed by Parliament. Someone appointed rather than inheriting or in Jessica's case, assuming the mantle of a for-life position is not to my liking. But, that's BT.
And my point is, that whoever tried to topple the state or the C-G had never found it diffcult to rally some support. That is because the abovementioned fracture lines were always there. All a rebel had to do was to stick a wedge into one of the fracture lines and push.
And mostly, he didn´t even have to push very hard.
Ryan Steiner, Michael Hasek-Davion, the Von Rohrs and Katrina Steiner would agree. Rebellions and coups are built on existing opposition to the current status quo.