Nebraska has certified two ballot measures to legalize medical marijuana even though the state’s Republican attorney general says their supporters may have submitted at least several thousand invalid signatures. Attorney General Mike Hilgers said Friday that the issues with signatures eventually could keep the proposals from becoming law despite their certification for the ballot. Hilgers and a local prosecutor also announced a felony charge against a petition circulator from Grand Island over 164 fraudulent signatures on 38 pages for the two separate initiatives. He said that if his ongoing investigation finds too many invalid signatures, the courts could take them off the ballot or invalidate new laws.