Conservative activists in Georgia and other states are using a new software tool as part of a broader effort to scrub voters from the rolls. As part of this initiative, they're asking election administrators to use their data to purge voter registrations, which means names could be removed in a less public process than a formal voter challenge.

A federal judge has ruled that Georgia can move forward with a planned purge of more than 300,000 inactive voter registrations Monday night. However, U...