Latest opinion polling from Spain shows that a potential alliance of leftist parties could perform well enough to deny a majority for the parties of the right at the next legislative election due to take place by Dec 2023 at the latest.

• The 'Sumar' (Unite) electoral alliance is not a prompted answer in most polls at present, with the main leftist Unidas Podemos - which is the junior partner to PM Pedro Sanchez' centre-left Spanish Socialist Workers' Party (PSOE) in the governing minority coalition - the party most often offered as an option for respondents.
• The 40db/El Pais December poll has the following median projected seats: Popular Party (PP): 115, PSOE: 96, Sumar (inc. Podemos & Mas Pais): 57, Vox: 43, Others 38, Citizens: 1.
• The same poll measuring Podemos and Mas Pais separately has the following seat projections: PP: 120, PSOE: 112, Others: 42, Vox: 41, Podmos: 30, Mas Pais: 4, Citizens: 1.
• Should the parties of the right (PP, Vox) fall short of a majority the prospect of them gaining power would be very slim. The 'other' parties are almost all regionalist parties of the centre-left/left, that would likely find it impossible to work with the far-right Vox, a staunch opponent of any devolution of powers away from Madrid.

Source: El Pais, 40db