When viewers in Chicago tuned their television sets to Channel 7 at 3 p.m. Sunday, they did not find "America's Funniest People" as the TV guides promised. Instead, they found Sen. Paul Simon (D-Ill.) and his challenger, Rep. Lynn Martin (R-Ill.), in a 60-minute joint question-and-answer session with Illinois voters.

What happened was not funny, especially to Martin, who was trailing by more than 15 percentage points in pre-debate polls and needed a clear breakthrough to get back into the race.

"She did fine," a Democratic consultant in another Illinois contest said, "but so did he. And under the circumstances, that wasn't nearly good enough for her."

The frustration of Martin, who has been the best-financed Republican Senate challenger in the country, reflects a general pattern of disappointment for the GOP in targeting Democratic incumbents. Simon has proved to be a case study of why incumbents are as hard to dislodge as the San Francisco 49ers.

On paper he is a tempting target. He won his first term in 1984 by only 89,000 votes out of 4.7 million cast. Four years later, he ran unsuccessfully for the Democratic presidential nomination -- a step that has almost invariably caused political problems for other officeholders who tried it.

Martin, a 10-year House veteran with close ties to President Bush, was so clearly well-positioned that no one even challenged her for the nomination. But even in a year when voters are indicating their restlessness with Washington politicians, she has not been able to make the race against Simon competitive.

Part of the problem, insiders in her campaign suggest, was that she was the victim of exaggerated expectations that may have bred overconfidence. "All the political insiders -- politicians and journalists, alike -- knew her well and she had 100 percent credibility with them as a Senate candidate," an adviser said. "But when we took our benchmark poll, only 18 percent of the voters knew her name."

When Martin's strategists decided to conserve funds by staying off the air during the summer months, she faded further from public consciousness.

Meantime, Simon was using his position as the incumbent senator to hold town meetings around the state and to conduct locally publicized hearings on hot topics, like the savings and loan scandals. He reaped a publicity bonanza when his assignments to the Foreign Relations and Judiciary committees put him in the middle of the Persian Gulf crisis and the confirmation of a new Supreme Court justice.

He also busied himself on the fund-raising front, collecting $7.2 million and going into the final month with $1.7 million on hand, while Martin was strapped enough to be forced to pull her ads on

Sept. 24. She is not yet back on the air.

Republican officials outside the Martin campaign say that she has not only been outspent but out-generaled, damaged by her inclination -- which she shares with many other House members making their first statewide race -- to keep campaign strategy decisions largely in her own hands. Although she hired three of the top Republican professionals -- pollsters Linda Divall and Robert M. Teeter and media consultant Roger Ailes -- even some Republicans say it has been hard to discern the central message of her campaign.

One result was that when Martin aired her first anti-Simon ads in late summer, playing off newspaper stories about favors he had done for big contributors, many voters reacted negatively to her attack on a man whose old-fashioned suits, glasses and bow-ties have created an image of preacher-like rectitude.

When Ailes last week applied the word "slimy" to Simon in an outburst at a news conference, the

reaction was such that Martin quickly sent the senator a note of apology.

By chance, that was the same day Simon pulled out of the long-scheduled first television debate. Citing the possibility of important Senate votes last Thursday evening, when the Channel 7-League of Women Voters debate was to be held, Simon canceled barely 48 hours before the event.

At noon the next day, Martin blasted him for "hypocrisy," pointing out that he never let Senate business interfere with a debate among the Democratic presidential candidates. But before her Chicago news conference could get onto the evening television news shows, Simon put his own spin on the story by announcing that he would be available for debate on Sunday afternoon.

As it turned out, the Senate adjourned more than four hours before the scheduled start of Thursday evening's debate, having taken only two lopsided roll-call votes on an appropriations bill and on a fishery act.

When she finally got Simon in her sights before the much smaller Sunday afternoon television audience, Martin did what neutral observers called a creditable job of pointing up the differences in their positions -- especially on taxes and spending. But, as the Chicago Sun-Times noted, Simon remained "imperturbable" as she tried to challenge his record.

No one in the Martin camp claimed the debate was a breakthrough, and one of her advisers said privately that "Simon's strategy of non-engagement" seemed to have prevailed.

They have one more scheduled debate on Oct. 25 -- and then it is over.

Special correspondent Lauren Ina contributed to this report.