The Libertarian Party, the nation's third-largest political party, charted a course for growth through pragmatic politics today by electing Alicia Clark, of Los Angeles, as its national chair.

Clark's victory, in a close, three-way contest, amounts to an endorsement of the policies championed by her husband, Ed Clark, in his campaign as the Libertarians' candidate for president last year. The Clark-for-President campaign emphasized grass-roots organization and a "gradual," phased-in approach to the party's program for slashing foreign and domestic government programs.

Ed Clark's presidential campaign was sharply criticized during the party's national convention here this weekend by a sizable faction that said the party's best course would be to become "more radical" and thus try to appeal to voters who are fed up with the major political parties.

Clark defeated John Mason, a leader of the "more radical" faction, by a vote of 273 to 228 on the third ballot of the election for chair. Another 35 delegates, reflecting the undercurrent of anarchy in the party, voted for "none of the above."

Despite the choice of the relatively moderate Clark as chairman, the party platform approved here sets forth a program that is thoroughly radical by the standards of mainstream politics.

Based on the principle that government should be "noninterventionist" on both foreign and domestic issues, the platform calls for repeal of all "victimless" crime laws -- including laws against drugs, prostitution, gambling, pornography, suicide and abortion. It would eliminate foreign aid and restrict the military to defense against direct attacks on U.S. soil. It would turn such government programs as Social Security, public schools and air traffic control over to the private sector.

The nine-year-old party was on the ballot in every state in the last election -- the first minor party to achieve that goal -- and Ed Clark won about 1 percent of the presidential vote nationwide.

The new chairman said here that Libertarians must try to make their positions sound reasonable and gradual so as not to scare away mainstream voters.

Sheldon Richman, of Washington, D.C., an economist at a free-market lobby group, was elected vice chair.