Tremors from "the Anderson difference" already are being felt in the 1980 presidential race. If John B. anderson's share of popular support as an independent rises another six or eight points among US voters -- from 24 percent in the latest survey, to 30 percent -- tremendous pressures and excitement would be generated in the Democratic and Republican camps, political experts say.
In an election contest where swings of 10 or more points in candidate support have been common, the possibility of such a rise in voter strength for Mr. Anderson is not discounted by pollsters.
The 30-point threshold is considered crucial. Crossing it would help convince voters that casting their ballots for the Illinois congressman would not be wasted, thus shoring up his support. And it would create a three-man race for the White House, with tactical and constitutional repercussions.
Already, Mr. Anderson has emerged as a target of the Republican National Committee on his right and the arch-liberal Americans for Democratic Action (ADA) on his left. President Carter's campaign lawyers are "looking at ballot- access laws in different states" to ready a legal blockade, if necessary, to limit losses in November to the Illinois congressman, a Carter-Mondale campaign spokesman says.
Republican leaders worry that a strong Anderson drive could deprive both the GOP and Democratic nominees of an Electoral College majority, thus putting the election into the House of Representatives, where the Democrats have an advantage. The ADA argues that Mr. anderson is "not a true liberal" -- warning that the independent candidate would help elect Ronald Reagan, who the ADA fears might undo liberal gains of recent years.
The Carter-Mondale campaign sees Mr. Anderson making inroads in states where the President himself is strongest -- cutting more directly into Mr. Carter's strength than into Mr. Reagan's.
This point is dramatized by outside analyses. William Schneider, a political scientist at Stanford University's Hoover Institution, places 10 of Mr. Anderson's 13 best states among those leaning toward Mr. Carter -- Connecticut, Massachusetts, Minnesota, Maine, Oregon, and Wisconsin. The other three states where Mr. Anderson might be a factor -- California, Illinois, and Iowa -- also could be crucial to Mr. Carter in November.
"The big change in the presidential equasion is Anderson, not Iran," says Richard Scammon, president of the Elections Research Center. "The problem will be torn voter, chiefly the liberals who can't vote for Reagan. As of now, we don't know how this swing group will vote -- whether for Anderson or for Carter to keep Reagan out of the White House."
Pollster I. A. Lewis -- whose lates national survey for the Los Angeles Times at the end of April put Mr. Anderson at 24 percent, President Carter at 38, and Mr. Reagan 32, with 6 percent undecided -- says, "The polls will have a lot to do with Anderson's success."
"If the polls are high for him, it won't seem like a thrown-away vote in November," Mr. Lewis says.
However, he cautions that national and international events could play havoc with traditional state-counting in calculating 1980 prospects.
"This year, outside events may have more effect than traditional forces," says Mr. Lewis. "If the United States gets into a really hard place with Iran on Afghanistan, Carter will be re-elected," Mr. Lewis asserts. "If there is a hard economic siege, Reagan will win."
Mr. Lewis's survey, taken April 26 and 27, shows Mr. anderson a little closer to the critical 30 percent vote threshold than previous findings, where he and the President and Mr. Reagan would entangle in a three-way race.
But the Anderson standing with voters could fade much as Senator Kennedy's has since last fall, when he led Mr. Carter by 2 to 1 among Democratic voters, Mr. Lewis observes.
Meanwhile, Mr. anderson's lawyers are "prepared and willing to go to court" to defend his access to the ballot in the 45 states where candidates can still file for president, says Edward Coyle, assistant Anderson campaign manager.