EIA made a coalition with the Basque section of the Communist Movement of Spain (Movimiento Comunista de España), creating a coalition named Euskadiko Ezkerra.
In 1979, deputies (congressmen) Xabier Arzalluz of the Basque Nationalist Party (PNV) and Juan María Bandrés of Euskadiko Ezkerra, affirmed that Article 8 of the then-new Statute of Autonomy of the Basque Country was intended to integrate the enclave of Treviño into Álava and the enclave of Villaverde into Biscay.