With the Illinois primary on March 15, 2016, Republican Illinois Senator Mark Kirk bought an $800,000 ad buy to attack Democratic senatorial candidate Rep. Tammy Duckworth. "Security" hits Duckworth for calling to allow Syrian refugees into the United States. The ad also tries to convince voters that Duckworth, an Iraq war veteran and Purple Heart recipient, won't protect American families – which may be a hard sell for voters who know her background. Many political pundits believe Duckworth will be a formidable challenger against Kirk in the General Election, assuming she is the Democratic nominee. By releasing this attack ad before the Democratic primary in March, Kirk's campaign is hoping to close the gap in Duckworth's growing lead. "Security" is an updated version of Kirk's December 2015 attack ad, "Big Differences."