The two followers of Lyndon H. LaRouche Jr., who won statewide victories in this month's Democratic primary, received strong support throughout the state and did particularly well in certain heavily black wards in Chicago, an analysis of the election statistics shows.

Democratic Party leaders have dismissed the victories of Mark Fairchild for the lieutenant governor nomination and Janice Hart for the secretary of state nomination as a fluke. But an analysis of the election statistics suggests that some voters may have been voting against the regular Democratic candidates, without necessarily knowing that Fairchild and Hart were LaRouche followers.

This seems most apparent in the race for secretary of state, where the defeated candidate was Aurelia Pucinski, a veteran Cook County official whose father, Alderman Roman Pucinski, is a powerful member of the Chicago Democratic organization that has been at war politically with Chicago's black Democratic mayor, Harold Washington.

Hart captured 98 of the 102 counties in Illinois in defeating Pucinski for the secretary of state nomination and did especially well in heavily black wards in the city. In the 14 wards where blacks make up more than 80 percent of the voting-age population, Hart took 74 percent of the vote to Pucinski's 26 percent. At the other end of the spectrum, in the 13 wards where blacks of voting age make up less than 2 percent of the population, Hart got 27 percent to Pucinski's 73 percent.

Fairchild took 78 of the state's 102 counties in his primary victory over state Sen. George Sangmeister, who comes from Will County south of Chicago. In the 14 wards with the greatest concentration of black voters, Fairchild got 62 percent of the vote to Sangmeister's 38 percent. In contrast, Fairchild got 44 percent to Sangmeister's 56 percent in 13 wards that are less than 2 percent black.

Neither of the LaRouche candidates won heavily populated Cook County, but their showing in the city's black wards and in downstate Illinois, which often is hostile to the Chicago Democratic organization, provided the margin of victory.

Adali E. Stevenson III, who won the Democratic nomination for governor, now plans to leave the party to run as an independent rather than be paired with Fairchild in his quest to defeat Gov. James R. Thompson (R) in the Nov. 4 general election.

Fairchild and Hart ran as Democrats, but are backed by an organization calling itself the National Democratic Policy Committee, the political group run by LaRouche, who lives in Leesburg, Va. LaRouche, once considered a left-wing extremist, more recently has been described as an ultra-right conservative, although categorizing his politics remains difficult. He has run for president several times, receiving small numbers of votes.

LaRouche and groups tied to him urge repeal of the Gramm-Rudman-Hollings budget control act, call for a strong national defense that includes the president's Strategic Defense Initiative, advocate the screening of all Americans to detect AIDS and seek the quarantining of those with acquired immune deficiency syndrome until a cure is found.

The voting statistics come in part from unofficial tallies compiled by the Illinois Board of Elections. The analysis of voting patterns in Chicago and some of the downstate counties was prepared for The Washington Post by Election Data Services (EDS), a Washington-based political consulting firm that specializes in geographic analysis of election returns. EDS has worked for the Cook County Democratic Party headed by Alderman Edward R. Vrdolyak.

Fairchild, a graduate of the University of Illinois, got better than 57 percent of the vote in 54 of the 78 counties he carried.

In the "Little Egypt" section of southern Illinois, he captured 14 of the 16 counties, eight by better than 57 percent.

A huge Democratic vote in populous Chicago and Cook County cut Fairchild's overall margin of victory to about 52 percent of the total of about 600,000 votes cast. Put another way, 64 percent of loser Sangmeister's vote came from heavily Democratic Cook County.

These trends were etched even more clearly in the Hart-Pucinski contest. Of the 98 counties she won, Hart took 61 by 67 percent of the vote or better. Chicago and Cook County voters heavily backed Pucincki, the party candidate, accounting for 73 percent of her total vote.

Less than 20 percent of the 6 million Illinois voters turned out for the primary.