Rahm Emanuel is expected to appeal against a decision banning him from running for mayor of Chicago.
Mr Emanuel, formerly President Barack Obama’s chief of staff and a onetime senior aide to Bill Clinton, has been declared ineligible for the vote on February 22 because he has not been a resident in the city for long enough.
An Illinois court said that Mr Emanuel did not qualify to appear on the ballot because he had not lived in Chicago for the last year.
The son of a former Irgun fighter, Mr Emanuel was born in the city. He said that he remained a resident because he owned a home in Chicago, which was merely rented out while he was working in Washington DC.
Mr Emanuel, who previously served as an Illinois congressman, gave up his White House position last year to concentrate on the mayoral bid. He vowed that the decision would not stop him and said he would appeal to the Illinois Supreme Court.
Mr Emanuel said: "I have no doubt that we will in the end prevail at this effort.
“This is just one turn in the road. The people of the city of Chicago deserve the right to make the decision on who they want to be their next mayor."
Mr Emanuel is hoping to succeed Chicago’s longtime mayor Richard Daley, who announced last year that he was stepping down after 22 years in office.