Mr. Clinton was flanked on stage by several high profile democratic candidates including Gov. Quinn and state treasurer Alexi Giannoulias who are both in tight races.
Most of what the public hears in U.S. Senate campaign television ads are Mark Kirk and Alexi Giannoulias trashing each others' character. But there are issues in this race. ABC7's Charles Thomas took a look at some of the questions to which the candidates give different answers.
The nearly $800 billion American Recovery and Reinvestment Act -- better known as the stimulus -- was designed to put Americans back to work during the recession. In the race for Illinois' open Senate seat, whether or not it was effective is a key difference between Republican Mark Kirk and Democrat Alexi Giannoulias.
"The recovery act has not been a perfect bill but the question is what would have happened if we didn't have it and economists across the board will tell you the recovery act helped stem a second Great Depression," said Giannoulias.
"One of the tragedies of the stimulus is it limited projects to shovel-ready projects which means the big payoff projects, which for example in Illinois, would have been fully funding the O'Hare modernization project, or a new lock and dam system for the Mississippi River," said Kirk. You believe that should have been funded? If that was funded we would have a long term economic payoff."
On future economic policy, North Shore congressman Kirk's slogan is 'tax less, spend less and borrow less.'
"Any way that we reduce spending will help out the economy and the long-term future of the United States so that we don't become a debtor nation in hock to every other country in the world," said Kirk.
But Giannoulias says Kirk voted for eight budgets during the Bush administration that worsened the federal deficit. The Illinois treasurer says future tax cuts should focus on small businesses.
"I believe in a job creation tax consideration for small businesses that hire right now. I believe in a payroll holiday for low to moderate income workers…We need to do everything we can to encourage the private sector to start hiring," said Giannoulias.
Another issue concerns partisanship. Democrat Giannoulias says he'll support the president's agenda while insisting he will not be the administration's a rubber stamp.
"I have said repeatedly that I am going to vote my conscience, and if that means if I disagree with Harry Reid, if I disagree with the administration, then I'll say so," said Giannoulias.
And Kirk promises not to join what some critics call an obstructionist Republican minority.
"I have been very independent. I backed stem cell research, I have backed the S-CHIP program for low income kids having health insurance," said Kirk.
The candidates differ on immigration policy. Kirk says the Dream Act to allow undocumented students to go to college or join the military should not be considered until after the nation secures its borders.
"If we make sure for the homeland security of the United States, we accomplish a fundamental mission of who is coming in the country, we reward legal immigrants who have played by the rules, then we open up the space for the rest of the debate," said Kirk.
"I am in favor of the Dream Act, I am in favor of comprehensive immigration reform," said Giannoulias. "We can't afford to tear these families apart, these are young men and women, who want a chance, a shot at the American dream."
The candidates also disagree on the Citizens United Supreme Court decision that allows corporate money to fund political ads. Kirk says those who buy the ad time should disclose their donors but he does not support a constitutional amendment to reverse Citizens United. Giannoulias says the decision has had a dangerous impact on our democracy and would vote to reverse it.
There are candidates running for U.S. Senate from the Green Party and Libertarian Party as well.