WASHINGTON, DC - JULY 15: U.S. President Barack Obama speaks about reform of the financial regulatory system on the South Lawn of White House July 15, 2010 in Washington, DC. Congress passed reform legislation July 15, that will set new regulations on banks and financial institutions in response to the economic crisis. (Photo by Brendan Smialowski/Getty Images)
News of the visit comes after the Illinois state treasurer brought in significantly less money than his Republican opponent.
Giannoulias announced last week that he had raised $900,000 in the quarter that ended in June, compared to the $2.3 million hauled in by Republican Mark Kirk.
Kirk is a congressman from Chicago's northern suburbs.
It will be an embarrassing defeat for Democrats if they lose in November the seat that Obama relinquished after he was elected president in 2008.