Democrat Michael Dukakis, poised to lock up his party's presidential nomination with Tuesday's final quartet of primaries, dropped his customary caution to exult that "victory is in the air." But remaining rival Jesse Jackson looked back with pride, calling his historic candidacy a "catalyst for growth."

Republican George Bush, who has the GOP nomination in the bag, expressed eagerness to face Dukakis in the fall. He said the two have many differences and "I am . . . on the right side."The four-month presidential primary season closes Tuesday with races in California, New Jersey, New Mexico and Montana. All three presidential contenders were in California Tuesday, and all were staying in the state tonight to wait out the results of the day's contests.

The biggest prize is California, and an ABC News tracking poll indicated Dukakis led Jackson in the state by a 2-1 margin, 61 percent to 30 percent. The survey, based on 415 interviews Saturday and Sunday, had a margin of error of 6 percentage points, the network reported Monday night.

California officials were predicting a low turnout, however. Secretary of State March Fong Eu said she expected a turnout of 48 percent, which would be the lowest in more than 40 years.

Before Tuesday's voting began, Dukakis had nearly 1,900 delegates, leaving him fewer than 200 shy of the 2,081 needed to nominate. On Monday alone, more than 70 delegates flocked to the Dukakis camp. Jackson trails with less than 1,000 delegates.

There were 466 delegates at stake in Tuesday's primaries.

In addition, Dukakis' former rivals for the nomination were lining up behind him. Campaign sources said Dukakis would travel to Missouri on Wednesday, the day after the last primaries, to pick up Rep. Richard Gephardt's endorsement. The same day, the sources said, Sen. Paul Simon of Illinois was to endorse the Massachusetts governor in Washington.

Dukakis, not noted for his effusiveness, nonetheless sounded like a happy man as he headed into the final contests.

"I'm really overwhelmed by the good feeling, the spirit, the confidence. A sense of victory is in the air," he said as he campaigned Monday in Los Angeles.

Jackson, however, suffered a primary-eve embarrassment when he got stuck in traffic and missed the first 16 minutes of a live broadcast.