And yet its leaders misjudged the public and it suffered a severe setback.
It was supposed to be a historic moment for the left in Europe.
Podemos – the anti-austerity party founded barely two years ago – was set to become Spain’s second force in Sunday’s re-run of December’s inconclusive election and perhaps be in a position to enter government in a leftist coalition.
The polls were unanimous in this respect.
Some people even began to think that perhaps the pollsters were being coy and Podemos might just end up snatching the election from the jaws of the conservative People’s party.
Why did the polls get it so wrong?
It’s probably a matter of expectations.
The rise of Podemos has happened so fast that everybody – those who loved it and those who loathed it – assumed it would continue to grow indefinitely.
Pollsters joined in this groupthink and overestimated the party’s prospects.
And yet there have been hints that not everything was as it appeared.