The case, implicitly, for Britain's new breakaway Social Democratic Party-by one of the four former Labour government ministers who comprise its collective leadership. Williams' call for a fresh start will disappoint anyone who expects a manifesto: she is moderate, reasonable, concerned (though not, like the title, pappy). Anyone accustomed to American party-platforms, however, or the writings of prospective American candidates, will be cheered by her clear-eyed appraisal of Britain's problems and her recourse to remedies effective elsewhere. She first lays out where-we-are. The achievements of 30 years of ""welfare democracy"" are threatened by the prospect of little or no economic growth. Big government is unpopular-witness the taxpayer revolts on the one hand, the small-is-beautiful stirrings on the other. ""Traditional socialism,"" committed to state-ownership, ""is obsolete."" Economic pluralism, Williams avows, is inseparable from political pluralism--her one distinct break with standing (if low-profile) Labour Party policy. On the what-to-do side, her strongest, most attractive stand is her refusal to accept lasting unemployment. The factor of labor has been minimized against other factors of production, she writes, in part because ""labor is people, with their unpredictability, their moods and their wish to be consulted and informed""; in part because machines have been deemed less costly than people. But ""in some cases""--small firms, agriculture--""costs of production may be reduced by substituting labor for capital."" So Williams would alter the tax laws to encourage, not capital investment, but investment in people; she would foster small business--also more innovative--by curbing consolidation; she would arrange for young people, now the least-employed, ""an orderly transition from work to school."" And, mindful of class barriers to economic mobility, she would abolish fee-paying schools (a highly controversial view not shared, as far as one knows, by her co-leaders). In this connection, she lauds the community-wide American high school; and there are other observations (on supply-side economics, on the poor as scapegoats) that Americans might profitably take to heart. But chiefly this is the alternative to the present stand-off that Britons will have a chance to vote for at the next election-clearly and readably put forth.