CHICAGO - Reaching out to black voters across the state, Democrat Barack Obama had his campaign for a U.S. Senate nomination linked to the civil rights movement as he made an emotional appearance alongside the Rev. Jesse Jackson. Jackson urged his audience at a Chicago church to "vote to have a black man of substance in the U.S. Senate." Meanwhile, Republican front-runner Jack Ryan concentrated on building up downstate support in a series of appearances as he faced new calls to disclose more information about his divorce. His opponents suggest sealed court files contain embarrassing information that might come out after the primary and weaken a Ryan candidacy. But Ryan maintains the only information he is withholding involves his 9-year-old son. Primary voters on Tuesday will choose Republican and Democratic candidates to succeed U.S. Sen. Peter Fitzgerald, R-Ill., who is retiring. Obama joined Jackson at a South Side church, where Jackson recalled how Congress passed the landmark Voting Rights Act 39 years ago after civil rights marchers outside Selma, Ala. were met with dogs and police clubs on the Edmund Pettis Bridge. "We must never forget the blood of the cross or the blood on the bridge at Selma, Ala.," Jackson said. Obama, leading in all recent polls, sought to fire up supporters to produce a big turnout Tuesday, saying, "I need you to carry me across the finish line." Dan Hynes, Obama's closest rival in the polls, worked the crowds at the traditional South Side St. Patrick's Day parade. As bagpipes wailed and drums boomed, he complained about the campaign's focus on divorce and other personal issues. Hynes called it "unfortunate for the voters because it's overshadowed the real issues in this race, so the voters haven't seen the opportunity to talk about health care and jobs." Ryan's rivals sought to raise doubts about whether he could be elected in the fall, although Ryan says nothing damaging is contained in the sealed portions of the files of his divorce from actress Jeri Ryan. One of Ryan's Republican rivals, dairy owner Jim Oberweis called for Ryan to "clear the air" by letting someone impartial view the records and assure voters there was nothing of concern. He suggested former Gov. Jim Edgar or Cardinal Francis George of Chicago. At a GOP dinner in Peoria, Oberweis met briefly with Ryan to discuss the proposal, but Ryan again turned it down. Several downstate Republican officials, while stopping short of calling for Ryan to release the information, said they fear details of Ryan's divorce will come out eventually. "If he's the nomination of our party, there's no doubt that it's going to be disclosed. That's just the way things happen in politics," said U.S. Rep. Ray LaHood of Peoria, who backs Andy McKenna in the Senate race. Ryan told reporters the papers are sealed to protect his son, Alex. "I've been specifically saying to everybody, whether it's the press or members of the Republican Party, that the stuff that surrounds the documents of my son, those are private," Ryan said. "I don't think anything to do with my son or my family should be part of this campaign," Ryan said. "They are not running for office. It's just me." A campaign aide to a rival candidate, retired Air Force Gen. John Borling, on Wednesday made unsubstantiated claims concerning potentially embarrassing material he said was in the files. Campaigning at the St. Patrick's Day parade, Maria Pappas bewailed the increasingly nasty tone taken by the race. "It will forever go down in history as the sexual perversion and drug-use campaign," Pappas said. "If you didn't have a glitzy sex life and you weren't using drugs, you couldn't get covered. It's overshadowed everything. You almost had to be a unicorn to get coverage here." A Copley News Service poll released Sunday showed Obama with 37 percent, Hynes 18 percent, commodities trader Blair Hull 16 percent, and other Democrats in single digits. Among Republicans, it showed Ryan with 45 percent, business executive Andy McKenna 12 percent, Oberweis 11 percent, state Sen. Steve Rauschenberger, 7 percent, and the rest trailing. The telephone survey of 400 probable voters in each party by Washington-based Mason-Dixon Polling & Research had an error margin of plus or minus 5 percentage points. It was conducted Monday through Wednesday, before the controversy over Ryan's records heated up. --- Associated Press writers Mike Robinson, Ginny Skalski and Christopher Wills contributed to this report.