  With a majority of 'Yes' votes in the Constitutional Referendum of 2017,
Turkey continues its transition from democracy to autocracy. By the will of the
Turkish people, this referendum transferred practically all executive power to
president Erdogan. However, the referendum was confronted with a substantial
number of allegations of electoral misconducts and irregularities, ranging from
state coercion of 'No' supporters to the controversial validity of unstamped
ballots. In this note we report the results of an election forensic analysis of
the 2017 referendum to clarify to what extent these voting irregularities were
present and if they were able to influence the outcome of the referendum. We
specifically apply novel statistical forensics tests to further identify the
specific nature of electoral malpractices. In particular, we test whether the
data contains fingerprints for ballot-stuffing (submission of multiple ballots
per person during the vote) and voter rigging (coercion and intimidation of
voters). Additionally, we perform tests to identify numerical anomalies in the
election results. We find systematic and highly significant support for the
presence of both, ballot-stuffing and voter rigging. In 6% of stations we find
signs for ballot-stuffing with an error (probability of ballot-stuffing not
happening) of 0.15% (3 sigma event). The influence of these vote distortions
were large enough to tip the overall balance from 'No' to a majority of 'Yes'
votes.
