Washington — Rep. John B. Anderson (R) of Illinois reportedly has bought the argument that because so many voters are dissatisfied with Ronald Reagan and President Carter he could win as an independent candidate.
Even now, Mr. Anderson is spending several days in deliberations, preparing, it seems, to announcing his decision to challenge the eventual GOP and Democratic Party nominees.
Mr. Anderson is understood to have accepted the thesis that he would not be merely a "spoiler" -- pulling just enough votes to help defeat one or the other of the major candidates. He is convinced, his associates say, that he could do what the most successful third-party candidate of the past, Teddy Roosevelt, could not do -- win the election.
Mr. Roosevelt won 28 percent of the popular vote as the Progressive Party candidate in 1912.
Mr. Anderson, at this point, seems encouraged, not discouraged, by polls which show he could win some 18-20 percent of the vote in a three-way contest with Messrs. Carter and Reagan. He apparently feels he could build on this base to fashion a victory.
Yet Monitor soundings among political observers and key politicians have produced this assessment of an Anderson third-party candidacy:
Mr. Anderson would likely affect the outcome in November, but it is unlikely he could come close to winning.
Polls indicate the Illinois congressman drawing equally from Messrs. Carters and Reagan at this time. But the conventional wisdom in Washington political circles is that Democratic liberals who now back Sen. Edward M. Kennedy would move quickly over to support Mr. Anderson -- weakening the President and helping to elect Mr. Reagan.
Already, there is considerable evidence that this will occur in the one liberal state, Massachusetts, that voted for Sen. Goerge McGovern in 1972.
Yet anexiety about an Anderson candidacy is also coming from Republicans. Bill Brock, GOP national chairman, says he will spend the next few days trying to persuade the congressman not to run.
The Republican concern is that the election pattern will be more like 1964 -- with the GOP moderates deserting a conservative candidate and contributing to a Democratic victory, this time by voting for Mr. Anderson instead of Mr. Reagan.
Some observers here see Congressman Anderson, even if he is unable to effectively challenge the GOP and Democratic Party nominees, still playing a useful role in the democratic process by giving those who are unhappy with the Carter-Reagan match-up someone for whom they can vote.