The deadline for residents to change their political party affiliation and to be eligible to vote in the upcoming 2012 primary election is December 31. State law requires voters to turn in party changes on the last day of the previous year in order to vote in the primary. The Jefferson County Clerk’s Offices and Motor Vehicle Service Center branches will be closed on Friday, however. The closure gives residents either today or Thursday to change their voter registration in person.Any voter registration cards that are mailed must be postmarked by December 31 to be accepted. State law does not forbid anyone from changing their party affiliation from January 1 to the date of the primary, but those voters are only given a non-partisan ballot.