Most developed countries, especially in Europe, ban mail-in voting to fight vast fraud and vote buying that had threatened the integrity of their elections, according to an exhaustive review of voting rules and histories in over 30 major nations.

In the European Union, 63% have put a ban on mailing in ballots except for citizens living overseas. Another 22% have imposed a ban even for those overseas. And most of those that allow mail-in ballots require some form of photo ID to get one, according to the report from the Crime Prevention Research Center shared with Secrets.