Elections in Spain

On June 26th, 2016, there were new parliamentary elections in Spain, as none of political parties were able to gather support to make up a government after elections on December 20th, 2015.
During this summer time, we met many electoral surprises. Firstly, participation was reduced by almost 4 points respective of 2015 (from 73.2% to 69.84%). 
This can be a sign of certain tiredness in respect to politics. There are no significant differences between a blank vote or a null vote.
There was a change of voting for political parties in the Congress of Deputies, since it is the chamber where the president of the government is chosen.
The party with the most votes is the PP (Partido Popular), which obtained 700,000 votes more than in past elections and has 137 seats (14 more than 2015). PSOE (Partido Socialista) remains the party with the second most votes, and despite getting a similar number of votes in 2015, PSOE lost 5 seats compared to 2015 (due to Spanish electoral law). 
The convergence between IU (Izquierda Unida) and Podemos, named Unidos Podemos, has gotten a very negative result, taking into count that these two united parties got one million fewer votes than they obtained separately - 71 seats.
Ciudadanos has lost around 400,000 votes and 8 seats, remaining with 32 seats in this election. The rest are little parties from regional ambit, such as Catalonians from ERC (Esquerra Republicana de Cataluña) and CDC (Convergencia Democrática de Cataluña”), which still have 9 and 8 seats respectively. 
Regional Basques parties also had less votes than in 2015: PNV (Partido Nacionalista Vasco) lost 1 seat, leaving them with 5 seat, and on the other side BILDU kept 2 seats. Finally the Canarian party of CCa (Coalición Canaria) also got less votes than in 2015 but kept 1 seat. Regarding the Senate,results have been very similar. 
PP has obtained more seats than in 2015, increasing to 130 seats, which gives them almost the absolute majority (necessary for constitutional changes). 
The rest of the parties have retained similar trends just like those that were mentioned above about the Congress of Deputies. 
Without doubt, the most important details on this election are: Why PP has obtained 700,000 votes more than in past elections? And, why the coalition Podemos-IU got one million less votes in a coalition than campaigning separately?
In respect to the first question, it can be said that the PP received the 400,000 votes that Ciudadanos lost, and the other 300,000 votes, maybe, could come from voters who were in abstention in 2015. 
In this way, the campaign about a useful vote (against Ciudadanos) and the fear vote (against Podemos) has had a good effect and because of this the votes for PP increased. In respect to the second question, the one million fewer votes that the coalition Unidos-Podemos got could be found in the abstention that increased in more than one million people. 
And it could be because the coalition was unappealing to voters - both Podemos and Izquierda Unida, for some people, is like an alliance with radicals and for others is like an alliance with the establishment.
Still, it is too soon for more assessments because they will be more like a bet than an empirically probable forecast. But, again, it seems that it will be very hard to carry out a pact to make up a government, if the conditions of pacts after the elections of 2015 remains. 
As a political reminder, in Spain today there are four big political parties, which are classified on two axis: Right / Left. New Politics / Old Politics. 
Each one of those big parties have their own unique position on these two axis, namely: 
Partido Popular: Right and Old Politics. 
Partido Socialista Obrero Español: Left and Old Politics. 
Podemos: Left and New Politics. 
Ciudadanos: Right and New Politics.