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Rahm Emanuel's eligibility to run for mayor of Chicago has become the subject of scrutiny, even before the soon-to-be-former White House Chief of Staff officially announces his candidacy.

At issue is Emanuel's residency. Illinois election laws dictate that a candidate is only eligible to run for city office if he or she has been a legal resident of that city for a year prior to the election. For the Chicago mayoral election, this means Emanuel would need to have been a Chicago resident since February 22, 2010.

Critics say that because he decided to lease his North Chicago home last year, Emanuel forfeited his Chicago residency and thus can't run.

In an ironic twist, Mayor Richard Daley announced he would not seek reelection, thus opening the door for a possible Emanuel run, just days after the couple to whom Emanuel rented his house  reportedly renewed their lease. And the couple apparently refuses to terminate their lease early to allow Emanuel to move back in.

Election attorney Burt Odelson told Chicago radio show hosts Thursday that "the law is clear" in this case. "He rented his house out in September ‘09 and has not been back since, and has no residency in Chicago," Odelson said on WLS's Roe Conn Show. Odelson reportedly has ties to two probable Emanuel opponents in the mayoral race: state Senator James Meeks, a prominent pastor in the city's black community, and Cook County Sheriff Tom Dart.

Indeed, had Emanuel sold his Chicago home and registered to vote in Washington, he would be ineligible to run for mayor. But that's not the case. Emanuel is still registered to vote under his Chicago address, and in fact voted absentee in the February 2 Illinois Democratic primary.

Board of Elections spokesman Jim Allen likened Emanuel's situation to a soldier serving abroad. Military servicemen don't forfeit the right to vote in their home state just because they're not home to vote. Emanuel moved to Washington to serve under President Obama in a position that is intrinsically temporary, and so he is equally entitled to vote-and run for office-in his hometown.

Allen points out that no challenges to Emanuel's eligibility have yet been raised to the Board of Elections. In the likely event that one will arise-either from a rival candidate or private citizen- Allen told Fox the board will examine Emanuel's records and decide whether he has sufficient standing to run. And in the likely event that the elections board decides in Emanuel's favor, challengers can then take their claim to the courts.

The potential fracas over Emanuel's residency brings to mind claims that arose during the 2008 election-and persist today-that then candidate Obama was ineligible for the presidency because his birthright citizenship could not be proven. All of those challenges were thrown out as frivolous.

Though Emanuel will likely surmount challenges to his eligibility, he has perhaps a greater challenge in overcoming the outsider image rivals will surely pin to him. Emanuel served as an advisor to President Clinton for five years in the 1990s, then came back to Washington as a U.S. Congressman from 2003 until 2009, when he resigned that position to serve in Obama's White House.

Fox News Midwest Bureau Chief Todd Ciganek contributed to this report.