Rep. Mark KirkMark KirkGiffords, Scalise highlight party differences on guns Stale, misguided, divisive: minimum wage can't win elections Immigration critics find their champion in Trump MORE (R-Ill.) has a small lead over two potential Democratic opponents in the 2010 Illinois Senate race, according to a new poll released Monday.

Kirk took a 41-38 lead over Illinois state Treasurer Alexi Giannoulias (D) in a Rasmussen poll conducted last week. 17 percent of Illinois voters said they were unsure who they would favor, while four percent said they would prefer some other candidate.

By contrast, the centrist Republican commanded a wider margin over Chicago Urban League CEO Cheryle Jackson. 47 percent would favor Kirk in that matchup, while 30 percent would favor Jackson. Again, 17 percent said they were undecided, with six percent preferring another candidate.

According to the poll, Kirk has a 55-28 favorable/unfavorable rating with -- again, 17 percent -- not sure. Giannoulias has a 51-33 rating.

The poll, conducted August 11, has a 4.5 percent margin of error.