David Treen, candidate for governor, sat down on Santa Claus' knee at the Lake Forest Plaza Shopping Center this morning and said with a grin:

"I'm not going to cry. But you know what I need. I need 800,000 votes and I need them tomorrow."

Santa winked from behind his fake white beard. "I can give you one," the old man said.

"And I give you a gift too," Treen replied "I can bring you the gift of good government."

The encounter was one of those election-eve bits of frivolity in which politicians delight. But the gesture also had a touch of symbolism to it.

Santa Claus, it turns out, is a Democrat. His name in real life is Daniel Dever, and he has never voted for a Republican. Treen is a Republican candidate for governor, a dyed-in-the-wool conservative, and a fourterm congressman.

And if the polls are right, and if Santa delivers Saturday, David Treen will become the first Republican to be elected governor in the history of Louisiana.

"It will prove that being a Republican in Louisiana is no longer an anchor that automatically sinks you," said Treen, who has been running as a Republican in this traditional Democratic stronghold since 1962.

If Treen wins, it will be because he has the support of much of the state Democratic Party's hierarchy, including four major Democratic candidates for governor this year.

His opponent, Louis Lambert, is hoping Democrats will suddenly remember their roots Saturday and that a coalition of blacks and organized labor behind him will give him an upset victory.

Borrowing from the traditions of Huey and Earl Long, he has campaigned as an unabashed southern populist, railing against "the big city newspapers," the "eastern and norther interests," and the National Republican Party," which he charges as attempting to engineer a "second Louisiana purchase" in the election.

"We are at the crossroads in this election of whether we want to continue under Democratic leadership or whether you want to let the National Republican Party come in and grab you," he tells audiences.

"The Democratic-Party is a party of the farmer, the working man, small businessman and the schoolteacher.

"That's the kind of governor we need."

Seldom does a political race present such a clear-cut ideological conflict, a conflict between liberals and conservatives, a conflict between labor and management, a conflict between black and white.

Treen, a former member of the segregationist State's Rights Party, is a staunch conservative with an antilabor voting record in Congress. Lambert is running as a darling of blacks, labor and consumers.

Although a poll by The New Orleans Times-Picayune this week reported Treen leading by 47 to 31 percent, the race is expected to be close.

As Lambert sees it, the key issue in the contest is "sensitivity, compassion, feeling for the people." He has accused Treen of supporting right-to-work legislation and of consistently voting against the interests of blacks, senior citizens, the handicapped and organized labor.

As Treen sees it, "integrity is the overriding issue. We've run a very clean, responsible campaign," he told a news conference in the French Quarter today. "I believe the other side has not lived up to that standards."

The four Democrats Lambert beat in the Oct. 27 primary agree. Lt. Gov. James Fitzmorris, edged out by just 2,000 votes, filed suit after the election, charging widespread vote-buying, intimidation and manipulation of voting machines.

Fitzmorris lost the suit. But vote fraud charges have been common in elections her. "What I really couldn't understand," said one man who testified that he was given $25 to vote for Lambert, "was why he wanted to pay me that much money."

The suit had a devastating impact o Lambert, a state public service commissioner and former state senator. First it tied up him and his campaign staff for two weeks fighting legal battles (his legal fees were $150,000). He lost the momentum he had built up in his come-from-behind primary victory.

The suit also cast him as a heavy in the campaign. He became "the junkyard dog in the race" New Orleans columnist Iris Kelso wrote. "Nobody wanted to claim him."

State House Speaker E. L. (Bbubba) Henry, Secretary of State Paul Hardy, State Sen. Edgar G. (Sonny) Mouton and Fitzmorris, all defeated Democratic guvernatorial hopefuls, endorsed Treen and began campaigning for him.

Until two weeks ago, when he endorsed Lambert, Democratic Gov. Edwin Edwards remained silent. The impact of his endoresement and the ability of labor and black organizations supporting Lambert to bring out the vote are the big unknowns for the election.

Treen, meanwhile, has dispatched an army of poll-watchers to guard against vote fraud. "There's an atmosphere of intimidation and harrassment of supporters of David Treen, particularly in the black community," he said today. CAPTION: Picture 1, DAVID TREEN . . . "I need 800,000 votes tomorrow."; Picture 2, JAMES FITZMORRIS . . . charges widespread vote-buying