By contrast, Tamil Tiger rebels fighting for an independent state want a separate homeland for minority Tamils - which Rajapaksa, the president, rules out - and have repeatedly warned they will not lay down arms.
Rohan Edrisinha of the Centre for Policy Alternatives, an independent think-tank, said: "This is going to be a total disaster.
"Psychologically this is going to be a huge blow to the peace process, because it would suggest that the SLFP is going back to the early 1980s if not 1970s.
"The SLFP is offering less than what is already in place in the form of the 13th amendment to the constitution."
The amendment set up provincial governments.
"Viewed from the point of view of conflict resolution, it's really quite astounding."
The ruling party also proposes abolishing the executive presidency, adapting to a bi-cameral parliamentary system, ensuring that both the police and armed forces are more multi-ethnic, and that schools are more multi-lingual.
The Tigers were not immediately available for comment on these proposals, which a presidential committee has yet to combine with suggestions from other political parties to form a consensus devolution offer.
However, a 2002 truce is now dead on the ground, and the rebels and the military are locked in near daily land and sea battles, ambushes and bombings which have killed hundreds in recent months and which analysts expect to escalate.
Sri Lanka's military has vowed to wipe out the Tigers militarily and the rebels have warned of a bloodbath and of more air raids by its fledgling air force of adapted acrobatic light aircraft.
Meanwhile the conflict's toll of 68,000 is rising daily.