06/09/2010 02:34 pm ET Updated May 25, 2011

Mark Kirk Slips In Polls After Military Record Scandal, Still Slightly Ahead Of Alexi Giannoulias

After a rough few weeks for Illinois Senate candidate Mark Kirk, his poll numbers have dipped slightly--and 63 percent of those surveyed found the scandal surrounding his military record to be at least somewhat important.

After a boost in April, a Rasmussen poll conducted Tuesday shows Kirk back down to where he was before his opponent Alexi Giannoulias' family bank closure. As of Tuesday, 42 percent of those polled said they supported Kirk in the race for President Obama's former Senate seat. In April, he was polling at 46 percent.

Giannoulias had support from 39 percent of those polled.

Rasmussen surveyed 500 likely voters in Illinois, and the margin of sampling error is +/-4.5 percentage points with a 95 percent level of confidence.

Kirk has been getting slammed by the press in recent weeks after a series of misstatements he made about both his military record and foreign policy came to light. The pollsters asked two questions about the military scandal:

How closely have you followed news reports about Mark Kirk and his military service?

27% Very closely
35% Somewhat closely
18% Not very closely
16% Not at all
3% Not sure

In terms of how you will vote this November, how important are Mark Kirk's misstatements about his military record?

27% Very important
36% Somewhat important
21% Not very important
11% Not at all important
4% Not sure

Meanwhile, Sen. Dick Durbin decided to use Kirk's negative attention to Giannoulias' advantage. In a letter sent out Tuesday to Giannoulias' supporters, Durbin wrote, "Contribute to Alexi Giannoulias' campaign for Senate today! As the Republican vying for President Obama's old Senate seat in Illinois comes under fire for embellishing his military record, voters should know they have a real choice."

The Kirk campaign has been quiet about the embellishment issue for several days now. In an email sent to supporters Tuesday, the campaign announced endorsements from Vets for Freedom and Republicans for Environmental Protection (REP). The email included quotes from military leaders about Kirk's "outstanding" service.

The REP endorsement comes after two other environmental groups crossed over to endorse Giannoulias. The Sierra Club and the League of Conservation Voters -- both of which have endorsed Kirk in the past-- say they were not pleased with Kirk's flip-flop on 'Cap and Trade' legislation.

The Capitol Fax blog's Rich Miller points out that the new poll numbers are not too bad for Kirk:

Kirk also has a slight advantage with intensity. While 15 percent have a "very unfavorable" view of Kirk, 23 percent have a "very unfavorable" view of Giannoulias. And while 13 percent have a "very favorable" view of Kirk, just 9 percent feel that way about Giannoulias.

Check out the full poll here.