MADRID - For decades Spanish politics was a two-horse race, but it has turned into a four-way tag-wrestling bout ahead of several potentially transformative elections this year.
The governing conservative Popular Party (PP) and mainstream opposition Socialists (PSOE) that have alternated in power since 1982 face an electoral assault on two fronts.
Spain's economy is gradually recovering from years of recession after a 2008 financial crash, but voters are still angry at the cutbacks imposed by the PP in that crisis and corruption scandals that have stained both the big parties.
Radical leftist party Podemos has for months been clipping their wings in opinion polls and in recent weeks another contender has surged into view: centrist party Ciudadanos ("Citizens").
Now, with local, regional and national elections lined up between March and November, new alliances may have to be made, analysts say.
"The PP and PSOE are two political parties, but Podemos and Ciudadanos are two social phenomena, and that is more volatile," said Ignacio Urquizu, a sociologist at Madrid's Complutense University.
Carving up the vote
A poll by Metroscopia published by centre-left newspaper El Pais on Sunday placed Ciudadanos in fourth place in voting intentions with the electorate carved up broadly evenly between it, PP, PSOE and Podemos.
With 18.4 per cent of the vote, Ciudadanos was just behind the PP which had 18.6 per cent, according to the poll. Ciudadanos' share has surged from 8.1 per cent in January and 12.2 per cent in February.
Podemos topped the Metroscopia poll with 22.5 per cent ahead of the Socialists on 20.2 - but no party had an absolute majority.
The poll came just three weeks ahead of the first of this year's regional elections, in the big southern region of Andalusia.
Its findings surprised analysts and the PP, which realises the challengers have the power to unify voters from various older but less powerful parties.
"It is a fact that we are going to have a very strong Podemos and a strong Ciudadanos, which will be eating up the smaller parties," said one PP lawmaker who asked not to be named.
"We will have to see what happens in Andalusia, and above what happens the day after."
Andalusia, a largely rural, farming zone and Spain's most populous region, is a traditional Socialist stronghold.
This year it will be an early gauge of Spain's changed political dynamic, which news website El Espanol has compared to four-way "tag-wrestling".
Several polls, including one by the state research institute CIS, have forecast the Socialists will come first in Andalusia but will fall short of an absolute majority, forcing them to choose a coalition partner - possibly Podemos or Ciudadanos.
Podemos has set its sights ambitiously on winning an absolute majority in the general election due in November, and has declined to speculate on any possible coalition choices.
Ciudadanos leader Albert Rivera however has admitted some kind of pact will be necessary.
"We are going to be the big surprise when we enter into the Andalusia parliament," he said on national radio RNE on Tuesday.
"An unstoppable change is on the way for the whole of Spain... a profound change in the political landscape." After the vote in Andalusia, the political trials of strength continue with a series of local and regional elections on May 24.
"They will allow us to take the true measure of support for the parties," said Urquizu.
"The post-electoral pacts will determine strategies for the elections that follow."
Hole in the right
Under Rivera, a 35-year-old Catalan lawyer, Ciudadanos shares Podemos's anti-corruption stance but is economically more liberal.
Podemos leader Pablo Iglesias, a 36-year-old university professor, has a pony tail and beard and wears jeans, while Rivera appears carefully groomed in a suit and tie.
Iglesias's left-wing economic proposals have put business leaders on guard, while Rivera's economic programme, drawn up by Luis Garicano of the London School of Economics, has been better received by the business world.
Urquizu said Rivera was profiting from disillusion among PP voters.
"Ciudadanos has filled a big hole in the centre-right," he said.