During the last referendum in Romania, the existing voting monitoring system did not work, creating doubt about the correctness of voting as this system allowed multiple voting detection:
Several non-governmental organizations asked today the Prime Minister Viorica Dăncilă to elaborate an emergency ordinance for the introduction of the Electronic System for Voting Monitoring and Prevention of Illegal Voting (SIMPV) for the Constitutional referendum on the 6th and 7th of October. We have also drew the attention to the many issues raised by the legislation referring to the organization of the referendum and the need to address these shortcomings in Parliament in order to meet international recommendations.
The referendum did not reach the required voter turnout for its validation, but this was still an issue.
I am wondering if the EU demands in any way (treaty, directive or at least a recommendation) for the mandatory usage of electronic systems to prevent voting fraud. Or is this simply considered a strictly domestic issue?
Question: How does the European Union ensure the correctness of elections with member countries?