Political Memo; Congressional Budget Battle Centers on Older Americans
Experts agree that political war now escalating over budget will revolve, in part, around interests and apprehensions of older Americans; both political calendar and issue agenda are pushing parties toward rough debate about who has elderly's best interests at heart; this year's critical Congerssional elections will play out amid increasing strains of aging society, slugging economy, resurgence in health care costs and disappearing budget surplus (M)