Rarely has Illinois had two such strong candidates spending so much - close to $3 million each - in a US Senate race. Incumbent GOP Sen. Charles Percy, seeking a fourth term, is proving an aggressive, resilient campaigner in his all-out effort to keep US Rep. Paul Simon (D), his bow-tied liberal challenger, from toppling him. Polls that showed the two running about even in mid-September now give Percy a slight lead.
Senator Percy, who considers himself a progressive and is chairman of the important Senate Foreign Relations Committee, has been endorsed by both the Chicago Tribune and the Chicago Sun-Times. But Mr. Simon, a five-term congressman from southern Illinois and former newspaper editor, has in hand many of the key labor, black, and other liberal endorsements that were once firmly in the Percy camp.
Business leaders and corporate political-action committees (PACs) also have contributed to Simon's campaign.
Percy has been sharply attacked by a number of single-interest groups, from the National Pro-Life Political Action Committee (although he and Simon have similar stands on abortion) to pro-Israeli PACs whose leaders argue that Simon is the stronger friend of Israel.
Simon, who draws much of his financial support from Jewish sources and favors moving the US Embassy in Israel to Jerusalem, argues that Percy, who favored the sale of AWACS planes to Saudi Arabia, has an ''Arab tilt.'' To help offset such criticism, former US Sen. Jacob K. Javits (R) of New York recently made an appearance in Chicago to underscore Percy's standing as a man of ''good faith'' among friends of Israel.
Although Percy drew the Rev. Jesse Jackson's endorsement and one-third of Chicago's black vote in his last election, Chicago Mayor Harold Washington's active involvement in a Simon ad campaign this time - accusing Percy of ''betraying us'' and of being ''bad for Chicago'' - is expected to keep black support for the senator minimal.
Like many Democrats these days, Simon favors some limits on free trade, a nuclear freeze, and a public jobs program. He wants more federal funds for education, job training, and expansion of medicaid. He argues that he can do a more effective job than Percy of bringing federal funds to Illinois. Often calling attention to Percy's personal wealth and reputation for aloofness, Simon stresses his opponent's support for corporate tax breaks and says the Republican is satisfied with the status quo.
Simon insists that Percy, who has not always supported Reagan policies in years past, has shifted to a stance of almost total loyalty now that the Chief Executive has become so popular. After Simon launched a series of ads that accused Percy of flip-flopping on a variety of issues, the senator's campaign produced a counterseries of ''Simon says ... (but) Simon does'' ads that suggest that Simon himself has been less than consistent. Percy paints his opponent as an ultraliberal who is ''addicted'' to taxes.
In a heated mid-October debate, Simon chastised Percy for an ad suggesting that the Democrat would raise taxes by $200 billion, or more than twice as much as Mondale proposes. Simon called the ad an intentional distortion of his position. Arguing that Percy's plan to reduce the deficit is ''right here on this blank sheet of paper,'' Simon stressed that his proposal was merely to close tax loopholes and cut federal spending. Percy said he could see why Simon was embarrassed, but that a tax by any other name is still a tax. Nonetheless he pulled his ad, at least temporarily, the next day.
Last of six pages on regional contests in the Nov. 6 election. Previous pages appeared Sept. 6 and 20, Oct. 11, 23, and 26.