"Act 23 addresses a problem which is very limited, if indeed it exists," Flanagan wrote.

He also wrote that the law doesn't provide alternatives, as other states' laws do, to prevent the exclusion of a qualified voter.

"Given the sacred, fundamental interest at issue, it is clear that Act 23, while perhaps addressing a legitimate concern, is not sufficiently narrow to avoid needless and significant impairment of the right to vote," Flanagan wrote.