[3] Rudy Clai officially entered the race on October 7,[4] but withdrew less than a month later, citing dysfunction within the Illinois Republican Party.

During the debate, Oberweis raised questions regarding International Profit Associates, a company that donated $100,000 to Lauzen's campaign and was being investigated for widespread sexual harassment and fraud.

[9] Democratic presidential candidate Barack Obama appeared in a television ad for Foster that ran immediately prior to the special election.

In contrast, Oberweis' campaign tactics were criticized, including the overuse of mass mailings and automated phone calls to remind voters of the special election.

[13] Reporter John Fund of The Wall Street Journal pointed to the failure of Lauzen to endorse Oberweis, Hastert's preference for "self-funded" but unskilled candidates, and local reviews that the NRCC ads were "nasty," "stupid," "largely incomprehensible" and "factless" as additional reasons why Foster won the seat.

[15][16] Although it was initially thought that Foster would not be sworn in until April due to the need to count absentee ballots before the election would be certified, he took the oath of office on March 11.