Constitutional Court upholds legality of ballot barcodes in 2026 general election

The Constitutional Court has ruled that there was no illegality in the use of barcodes on the constituency ballots and party list MP ballots in the 8 February general election, and that the allegedly disclosure of voter identities did not violate the Constitution.

The case stems from 22 complaints against the Election Commission (ECT) over the inclusion on ballot papers of controversial barcodes and QR codes. The Constitutional Court judges ruled, by 8 votes to 1, that the barcodes and QR codes on ballot papers were not unconstitutional.

The QR codes on constituency ballot papers had to be decrypted to reveal a number corresponding to one on the ballot booklet. Since each ballot booklet contained 20 ballot papers, The barcodes could reveal individual voter identities only under the specific scenario where all 20 voters receiving ballot papers from the same booklet voted for the same candidate. The Court stated that such a scenario was highly unlikely.

The Court concluded that the barcodes on the constituency ballot papers could not be used to identify how individual voters voted. 

The party list MPs’ ballots had a QR code on the top and barcode at the bottom. It was found that the barcodes directly revealed a number which matched the one on the ballot stub, making it possible to track individual voters and how they voted.

However, the Court stated that the identification of individual voters would require access to additional materials, including ballot stubs and voter lists, which were kept separately and securely. This made it impossible for ordinary citizens or even state officials to track individual voters, because when a voter enters a polling station, the polling official write on the ballot stub the voter’s number according to the voter list.

The Election Commission officials responsible for each constituency retain the ballots and ballot stubs, while the voter lists must be submitted to the local registrar within three days. As a result, it is impossible to access all three sets of documents.

The Court clarified that the secrecy o/f the ballot can be divided into two principles: “absolute secrecy” and “conditional secrecy”. Absolute secrecy requires that ballots be confidential, with no way to link ballot papers to individual voters This, however, contains the drawback is that all ballot papers will be identical, making them easier to counterfeit and making it difficult to investigate electoral fraud.

Under the principle of conditional secrecy, ballots remain confidential, but specific markings may be added to ballot papers in order to help prevent counterfeiting and electoral fraud. The Court noted that this principle reflects the intent of the Constitution.

The Court concluded that the barcodes and QR codes in this case were included to control the production of the ballots and to make it easier to track which constituencies specific ballot booklets were allocated to. They were also intended to ensure the integrity of the election administration process.

Ultimately, the Court concluded that the voting procedures in the 2026 general election did not violate the constitutional principle of direct and secret suffrage prescribed in the Constitution. To restore public trust, the Court also ordered the ECT to implement measures to ensure that ballots are designed without any traceable markings and are securely stored.

Barcode case saga

After the 8 February 2026 general election, the ECT, which had been allocated over 7.8 billion of taxpayers’ money to stage the election, faced a legitimacy crisis over the transparency of the polls. Serious concerns were raised by the discovery of barcodes and QR codes with unique numbers on ballot papers. 

Thai netizens raised concerns that each ballot paper may have been assigned a unique running number, as it was found that the 20 ballot papers in each booklet carried different numbers. The number on each ballot paper corresponded to the one on the ballot stub.

Each ballot paper could therefore be scanned to connect it to its ballot stub where voters are required to sign their names. The ballot stub also contains the voter’s number from the voting lists in each constituency. This made it possible to identify which voter completed each ballot paper and which MPs or parties they voted for.

On 13 February, the ECT argued that the election law allows it to prescribe codes or marks on ballot papers as a safeguard against “forgery”. The barcodes were also used to track the polling stations where the ballots were distributed, and that would help prevent ghost voting and electoral fraud.

The ECT also asserted that identifying individual voters was impossible. It said that this would require access to additional materials, including ballot stubs and voting lists, which are now kept separately, and that the Commission could not verify whether the numbers on the barcodes aligned with the ballot stubs as requested by the media and general public.

These concerns led to dozens of complaints filed with the Constitutional Court, asking for a ruling on whether the barcodes on ballots violated the secret ballot guaranteed in the Constitution. If it had ruled that the barcodes and QR codes violated the Constitution, the 8 February election could be declared void.

On 22 February, a re-run election was held in Constituency 15 in Bangkok’s Khan Na Yao District where citizens gathered at one polling station to observe vote-counting to ensure electoral transparency. They allegedly took photos of marked ballot papers and zoomed in to display the controversial QR code on each ballot paper. They then attempted to decode the barcodes in question to demonstrate that the elections lacked transparency.

The ECT later sued several citizens involved in this action for sedition and membership of an unlawful secret society. 

On 10 March, the Ombudsman resolved to forward to the Constitutional Court 22 complaints that it had received, noting that there were grounds to question whether the ECT infringed on voters’ rights and freedoms, potentially violating ballot secrecy.

On 18 March, the Constitutional Court judges resolved, by 6 votes to 3, to accept the 22 complaints forwarded by the Ombudsman.  

The Court held a witness hearing on 26 August. The witnesses included the ECT Secretary-General Sawaeng Boonmee, two other ECT officials, and two individuals from printing companies. On the following day, the Constitutional judges also conducted an on-site inspection of the venue where the ballot papers, ballot stubs and other relevant materials were kept.