New York Mayor Michael Bloomberg wants to make immigration a bigger issue in the presidential race, and he’s making his case in the candidates’ hometowns. Bloomberg started on Tuesday at a forum in Chicago.

The Partnership for a New American Economy hosted the forum and brought together more than 450 Republican, Democratic, and independent mayors and business leaders to drum up support for immigration reforms that the group hopes will create jobs. The partnership released a report on Tuesday that states that  immigrants started 28 percent of all new small businesses in the U.S. in 2011 and that immigrants are more than twice as likely to start businesses than their native-born counterparts.

Bloomberg told Chicago business leaders that immigrant jobs are essential to economic recovery, but he says neither President Barack Obama nor Mitt Romney has talked enough about that or other immigration issues.

“If [they] get elected what are [they] gonna do on these issues,” he asked, “And I think it’s fair to say that on virtually all of them, they literally duck any specificity.”

Mayor Bloomberg told business leaders that they can help sway campaigns, perhaps by holding back campaign donations.

Former White House Chief of staff William Daley joined Bloomberg in pushing for more attention to immigration policy.

“Why should kids from all over the world, the best kids intellectually that come here and study, basically not be encouraged to stay here,” he said, “and bring the talents and the resources from around the world to help us strengthen our economy.”

Mayor Bloomberg is expected to make a similar pitch to business leaders in Romney’s political base of Boston.