Rep. John B. Anderson was introduced tonight to the game of stick-the-front-runner, as his three rivals in next Tuesday's Illinois presidential primary took turns charging that he did not deserve the support of real Republican voters.

His fellow Illinois congressman, Rep. Philip M. Crane, told the most liberal of the GOP contenders, "You are in the wrong party."

George Bush said Anderson's refusal to pledge outright that he will support the Republican nominee means that he is trying to "divide a minority party."

And Ronald Reagan asked wonderingly, "John, would you really find Teddy Kennedy preferable to me?"

Anderson, the long shot who has surged into a surprising lead in the pre-Illinois-primary polls, defended himself vigorously, declaring, "I didn't know we had a loyalty oath in the Republican Party."

He told Bush, the erstwhile front-runner now struggling to avert elimination from the race, that his comments reflected the kind of "narrow partisanship" that might be expected of the "former chairman of the Republican Party under Richard Nixon."

And, despite the pressure from his competitors in the League of Women Voters-sponsored debate to say that he would back the GOP nominee, Anderson insisted that there were "certain fundamental issues" that could lead him out of the GOP in 1980.

The spirited 90-minute dialogue, which moderator Howard K. Smith often had to referee, reflected the tensions in the Republican battle with the approach of what everyone agrees will be the most important primary so far this year.

Former president Gerald R. Ford, who Smith said was watching the fray, was told by Reagan, Bush and Crane that he would be welcome in the race. But Anderson, dissenting as usual, said, "I would not want to see him disturb his well-deserved retirement."

Early in the day the Rockford, Ill., congressman expressed the hope that this would "be a warm and friendly evening." But the temperature was more than warm, and the atmosphere frequently less than friendly.

Crane opened the assult by saying that anderson had failed on some score cards to vote for moves to reduce the federal deficit -- a charge Anderson rejected.

Bush jumped in quickly to say that he "disagreed with John on cutting back on Social Security benefits . . . and favoring a 50-cent-a-gallon gas tax that would wipe out every working person."

Anderson replied that those statements, which will be repeated in new Bush ads for the Illinois campaign, amounted to "half-truths, and a half-truth is worse than a lie."

Anderson said that he proposed only to hold the cost-of-living increase in Social Security benefits to slightly below the rate of inflation, by eliminating the housing factor in that index, "but it doesn't mean the benefits will be reduced."

He said this proposal would save the Treasury $3.5 billion a year.

As for the gasoline tax, Anderson said most of it would be used to finance a 50 percent reduction in Social Security taxes.

Reagan jumped in to suggest that "when you raise one tax to cut another, the government always seems to come out ahead." Bush and Crane argued that the Anderson plan would penalize those now receiving Social Security benefits.

But that dispute was a mere warmup for the challenge to Anderson's repeated hints that he might take his candidacy into the general election as an independent if denied the Republican nomination and his statements that he could not support a Republican nominee who opposed the strategic arms limitation treaty with the Soviet Union. All three of his rivals have opposed SALT II.

Crane asked Anderson: "How can you ask for a Republican nomination when you have taken the position you will not support the Republican nominee?"

Crane also criticized Anderson for signing a fund-raising letter for the National Abortion Rights Action League, a political-action fund supporting candidates who oppose a constitutional amendment against abortion.

Crane cited several liberal Democatic senators named in that letter by "right-to-life" forces as targets for political extinction and asked Anderson how he justified helping such "ultra-extreme, left-wing Democrats?"

Anderson replied that the letter "was not in support of these individuals but to raise funds for an organization supporting freedom of choice" on abortion.

He said he thought no one in public life should be subject to "political exorcism because of the stand they take on a single issue."

But Reagan said that if such liberal Democrats can be defeated, "I don't care whether it's for one issue or 50, I'm for defeating them."

When Smith asked each candidate whether he was prepared to support anyone on the platform nominated by the Republican convention, Bush gave a flat yes, but Crane and Anderson indicated they would not support each other. Reagan said he had supported the Republican nominee ever since joining the party after spending his early life as a Democrat, but said "this is very difficult" because "I seem to hear a cry for another party being formed" by Anderson.

Anderson said election laws in most states, including California, would preclude him from running as an independent after seeking the republican nomination, so the risk of which Reagan spoke was not real.

But Anderson later highlighted his distance from traditional Republican views when he and the others were asked their model for the kind of Supreme Court justice they would appoint.

Reagan went back in history to John Marshall. But Anderson selected Hugo Black, a Franklin Roosevelt appointee who was noted for his liberal positions on civil rights cases and was a key part of the liberal coalition on the Warren court.

One point on which all four men agreed was that former secretary of state Henry A. Kissinger would not have an encore in their administration.