CO SB018

Requires voter registration applicants to provide proof of citizenship, established through a U.S. passport, birth certificate, naturalization document, naturalization certificate number (verified by county clerk), or any document accepted under federal immigration law.

Prohibits county clerks from registering persons who complete provisional ballot affidavits until they provide proof of citizenship.

Exempts persons already registered before July 1, 2011, and absent uniformed services electors or overseas electors applying by federal postcard application from the citizenship proof requirement.

Exempts registered electors from re-submitting proof of citizenship when changing address within a county, moving between counties with emergency affidavit, changing name, or changing political party affiliation.

Takes effect 90 days after final adjournment of the general assembly (August 10, 2011), unless a referendum petition is filed, in which case it requires voter approval at the November 2012 general election.