The incumbent left-wing president Nichi Vendola, who in 2005 surprisingly defeated a centrist in the centre-left primary election and then the outgoing President Raffaele Fitto, was under attack by his own coalition. Vendola, a gay communist President in a fairly conservative region, would have found hard to get re-election in a time when the centre-right led by Silvio Berlusconi was ahead of the centre-left both in Apulia and the whole country. Moreover Vendola, after having left the Communist Refoundation Party in early 2009, instead of joining the Democratic Party (PD), the largest party of the centre-left, started a small outfit named Left and Freedom and launched his bid.^[1][2]

The Democrats acknowledge that they needed a larger coalition in order to beat the centre-right and they were thus trying to convince Vendola to give up his bid and to endorse a more centrist candidate that could obtain the support of the Union of Christian and Centre Democrats (UDC) and Adriana Poli Bortone's I the South movement. Michele Emiliano, Mayor of Bari and PD regional leader, had been constantly mentioned as a possible candidate who would have received the support of the UDC.^[2][3][4] For her part Poli Bortone might have been interested in the race but her right-wing upbringing (she was a member of the Italian Social Movement and of National Alliance) would undoubtedly have stirred the left.^[5]

In a succession of events between late December 2009 and January 2010, Emiliano turned against Vendola^[6] (whom he supported until then), asked his party's regional assembly to unanimously endorse himself.^[7] The assembly of the party was suspended because of clashes between Emiliano and Vendola supporters,^[8] then Emiliano accepted to contest a primary election with Vendola^[9] and finally withdrew from the race,^[10] leaving the PD without a strong candidate.

Finally Vendola was chosen as candidate of the centre-left in a primary election on 25 January 2010.^[11]

The People of Freedom (PdL) of Berlusconi and former President Raffaele Fitto subsequently chose Rocco Palese, leader of Forza Italia–PdL group in the Regional Council and former Vice President of Fitto,^[12] while the UDC launched Poli Bortone.^[13]

After that Emiliano renounced his bid, the PD proposed Francesco Boccia as its candidate^[14] and the UDC endorsed him.^[15] However, as Vendola did not intend to withdraw from the race, the PD accepted to run a coalition primary election between Vendola and Boccia.^[16] This was a re-edition of the 2005 primary election, in which Boccia was narrowly defeated by Vendola.^[17]

On 25 January 2010 an unprecedented number of Apulian citizens turned out to vote in the primary and Vendola trounced Boccia in the primary, by winning over 67% of the votes cast.