An extract from The Survivors Story. Written in 2456.
The destruction of Romulus saw a new era for Romulan history. It was a truly tragic thing, watching a once major power being reduced to a third rate power. The once powerful fleet of warbirds was no longer meant for war, but for refugees becoming nomadic, struggling to survive.
The colonies accepted many from their lost planet, but only a certain number were permitted to actually live on the planets. Uninhabited moons and planetoids which hadn't served any purpose except to add to the empire's quota for planetary bodies, were colonised and built upon. They served as temporary homes, but they built up in number, eventually the resources of the planets started to strain themselves.
Federation vessels gave supplies, food, medical equipment, power cells. It was hard to believe that the ragged, emaciated refugees were once members of an empire. Politics was also a major weakness with the shattered empire.
The major colonies started to split into little groups. The destruction of Romulus, the death of the ruling body and the incident with the renegade miner known only as Nero, meant that Romulan society was fracturing and the Federation did nothing to help, believing that the Romulans would persevere and survive without much aid.
It was a sin that the Romulans would never forget. The Federation could've mustered the effort to help establish a new Romulan homeworld with a new government. Instead they didn't, ignoring the problems their wretched former enemies were suffering.
It may be a drift which may never heal. To this very day Romulan politics are fragmented.
( A/N - If you read Dr. Who's Remembrance of the Daleks you'll find that a major war fractured the Daleks into factions. The same principal is involved here.)