By any measure, Krupa until now has been a long shot to defeat Ald. Marty Quinn, a Madigan coat-holder. Krupa had to submit 473 valid signatures of 13th Ward residents to get on the ballot. In a legal filing, his attorney says Krupa delivered 1,729 signatures to the Chicago Board of Election Commissioners. Yet someone else filed 2,796 affidavits from residents seeking to revoke their petition signatures for Krupa. Affadavits are legal documents signed under penalty of perjury so surely none of them is untrue. But the math doesn’t work. Among possible explanations: