With the Welsh national elections on the horizon next year, the country's political landscape was shaken ten days ago by an earthquake that could foreshadow more significant shifts — one that may have major consequences not only in Cardiff but also in Westminster. On 23 October, Plaid Cymru, the Welsh nationalist party, achieved a historic victory in a traditional Labour stronghold in the Caerphilly by-election, around 20 kilometres from the capital. For a century of Westminster elections — and since 1999 in the Senedd (the Welsh Parliament) — the seat had been held by Labour. Against all odds, Plaid Cymru won with 47% of the vote, almost 4,000 more votes than Reform, which came second. Plaid secured 12,000 more votes than Labour, relegated to a humiliating third place. The Conservatives fared even worse.