By Richard Wood

Plaid Cymru’s manifesto for the 2026 election makes the case to reform the Senedd’s recently changed electoral system.

During the last Senedd session Welsh Labour and Plaid Cymru came together to reform Wales’ Additional Member System (AMS). AMS has ensured an element of proportionality in elections since 1999 but the dominance of constituency (much more so than in Scotland) has delivered only somewhat proportional elections.

The 2026 election is being held under a closed list proportional system with 16 multi-member constituencies, each electing 6 MSs.

Abolishing the First Past the Post element by replacing AMS was a welcome step forward, but closed list voting puts an incredible amount of power in the hands of parties. Moving towards the Single Transferable Vote or and open list system would address these concerns.

What does Plaid Cymru’s manifesto say on electoral reform?

Plaid Cymru’s manifesto notes that closed lists were not their preferred option for change.

They also call for a system that delivers real choice, ultimately backing STV for the Senedd and Welsh local government.

This is a positive step to improve proportionality, representation and voter choice at elections. However, if they do succeed in changing the system so soon they do run the risk of frustrating voters by changing things yet again. Their call to build consensus in the issue therefore matters considerably.

READ MORE: SNP could win unrepresentative majority on 29% of the vote, suggests MRP poll

What is Welsh polling saying?

Recent polls in Wales suggest Plaid Cymru could become the largest party in the Senedd, a significant change from Labour’s dominance since 1999 and at UK General Elections for a century.

Reform are biting at their heels for first place while the Greens hope to win their first MSs.

Meanwhile, polls suggest the Labour and Conservative votes are collapsing.

While the Lib Dems are hoping to keep their sole seat and gain another if possible.

READ MORE: Scotland’s STV council elections show England a better way of doing local democracy