Who checks the signatures?

Law on National Referendums, Legislative Initiatives and European Citizens’ Initiative (last amended in 2014)

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Article 24

Upon receiving a draft law or a draft amendment to the Constitution submitted by voters and signature sheets attached, the Central Election Commission shall count the signatures and verify whether signatories are eligible voters. If a draft law or the draft amendment to the Constitution is signed by not fewer than one-tenth of the citizens of Latvia who are eligible to vote, the Central Election Commission within three days shall notify the President of Latvia and send the President of Latvia the draft law or the draft amendment to the Constitution submitted by the electorate.