Dianne Feinstein scored a decisive victory Tuesday over John Van de Kamp in the battle for one of 1990's biggest political prizes _ the Democratic nomination for governor of California. All three major television networks "called" the election for her the instant the polls closed at 11 p.m. EDT. Voters in eight other states also set lineups for fall contests. The busiest primary night so far this campaign year saw North Carolina Democrats choose former Charlotte Mayor Harvey Gantt to challenge Republican Sen. Jesse Helms in the fall. Gantt, who defeated county prosecutor Mike Easley, got 57 percent of the vote and became the first black nominated for the U.S. Senate in North Carolina this century. "I'm ready to get into this fight" with Helms, Gantt said when he voted early in the day. "I'm ready to get it on with him." Both candidates campaigned more against Helms than each other. In California, Feinstein, the former mayor of San Francisco, beat Van de Kamp, the state attorney general, by 52 percent to 42 percents. The two spent millions of dollars battling each other, and Feinstein will plunge into an even more costly and just as nasty general election race against Republican Sen. Pete Wilson. He is trying to keep the California governor's office in GOP control. Wilson already has $3.5-million in his campaign bank account and there is speculation the GOP will spend close to $20-million in the race to succeed Republican Gov. George Deukmejian, who decided against seeking a third term. As usual, California voters also were making decisions on ballot propositions, including two that would strip the legislature of most of its power to redraw legislative, including congressional, district lines. California is likely to gain six U.S. House seats as a result of the 1990 Census. Another California ballot proposal would double the gasoline tax over the next five years and was being watched as a signal of a shift in sentiment in the state where the anti-tax revolt began in the 1970s. Voters also were choosing nominees in New Jersey, Alabama, Iowa, South Dakota, Montana, New Mexico, and Mississippi. In Iowa, Democratic Sen. Tom Harkin had no serious opposition and already was campaigning against Republican Rep. Tom Tauke in what looks like one of the tightest Senate races of the year. In a race in which abortion was a major issue, House Speaker Don Avenson won the Democratic contest for the right to oppose two-term Republican Gov. Terry Branstad. Avenson had 39 percent of the votes in early returns to 33 percent for Attorney General Tom Miller and 25 percent for former banker John Chrystal. Avenson and Chrystal support abortion rights, while Miller and Branstad are abortion opponents. In Alabama, Democratic Sen. Howell Heflin easily won nomination for a third term, setting up a November race against Bill Cabannis, who was unopposed in the GOP primary. But four Democrats waged a down-to-the wire fight in the primary race for governor. Educator-lobbyist Paul Hubbert had the early lead with 31 percent, followed by Attorney General Don Siegelman with 26 percent, former Gov. Fob James with 22 percent and Rep. Ronnie Flippo with 17 percent. No one was expected to get the clear majority needed to avoid a June 26 runoff between the top two finishers. Gov. Guy Hunt, a preacher-farmer who was thrust into the state's top office four years ago, easily defeated two minor candidates to win the GOP nomination. In South Dakota, Democrat Ted Muenster will try to take Republican Larry Pressler's Senate seat. Gov. George Mickelson had no GOP primary opposition as he seeks a second term. In November he will face former Democratic state Sen. Bob Samuelson. In Montana, businessman Bruce Vorhauer had the early lead over Lt. Gov. Allen Kolstad in the race for the Republican nomination to challenge Democrat Max Baucus for the Senate. In New Jersey, Sen. Bill Bradley breezed to victory in a barely contested Democratic primary, and Republicans and Democrats alike say he appears headed toward another easy win in November. Bradley next faces Republican Christine Todd Whitman in the general election. She had no primary opposition. Pro football player Phil McConkey was among those in the Republican primary for a congressional seat, but he was trailing state Sen. Richard A. Zimmer 44 percent to 32 percent in early returns. Marguerite Chandler was unopposed for the Democratic nomination. In New Mexico, Republican Gov. Garrey Carruthers was ineligible to seek re-election. Former Gov. Bruce King won the Democratic nomination in a bid to regain the office, and former state Rep. Frank Bond won the Republican nomination. _ Information from the Associated Press and Los Angeles Times was used in this report.