As he travels about the city, assuring Chicagoans that he is one of them, Rahm Emanuel must be asking himself why he just didn't leave his house vacant when he went off to work in the White House. Or rent it to a buddy or a relative.

That's because a cornerstone of an expected legal challenge to his status as a Chicagoan — a challenge that, if successful, would knock him off the February ballot and out of the city's mayor's race — is that when Emanuel rented his house he broke the rule that a candidate must live in the city a full year before the election.

"He doesn't have a house. ... He's not a resident if (he's) renting the house," said Burt Odelson, a Chicago election attorney who said he's filing a challenge against Emanuel with the city's Board of Election Commissioners as early as Friday on behalf of several "objectors" who he would not name.

Emanuel has tried to diffuse any question over his residency since the day he said goodbye to President Barack Obama at the White House, telling Obama that he looked forward to returning to "our hometown" and even throwing in a reference to the Chicago Bears.

Since then, he's made his family's history in Chicago part of his narrative, from his grandfather who arrived here from Europe to his own children, the fourth generation of his family to call the city home. He's talked of his father's Chicago medical practice and his uncle who retired as a police sergeant after working in a part of the city that Emanuel represented in Congress.

In recent weeks, Emanuel and his staff have ramped up efforts to do away with the issue. His staff posted newspaper editorials and a letter of their own explaining why Emanuel is a resident on his campaign website, ChicagoforRahm.com. In a campaign television commercial, Emanuel shakes hands with residents and city workers while stressing he's a Chicago guy, coming home to run for mayor.