absentee ballot acceptance testing alternet brennan center for justice certification of voting machines congressional research service dre voting machine election assistance commission electronic voting end-to-end auditable voting systems federal election commission hart intercivic independent testing authority independent agencies of the united states government independent verification systems international standard serial number national conference of state legislatures national geographic society national institute of standards and technology optical scan voting system overvote premier election solutions provisional ballot residual vote san jose mercury news secure electronic registration and voting experiment sequoia voting systems smartmatic software independence software verification undervote uniformed and overseas citizens absentee voting act united states department of justice civil rights division united states house of representatives united states secretary of defense united states secretary of health and human services united states senate usability testing voluntary voting system guidelines vote counting system voter verified paper audit trail voting rights act voting machine