Lisbon, Portugal: Antonio Costa, the leader of Portugal’s Socialist Party, was named prime minister and tasked with forming a government Tuesday after weeks of political instability caused by an inconclusive election last month.

The appointment comes after Costa’s anti-austerity alliance with Communists, Greens and the Left Bloc toppled the 11-day-old conservative minority government in a dramatic parliamentary vote earlier this month.

Portugal’s political difficulties are being closely watched in Brussels and Costa has sought to allay fears his anti-austerity drive could propel the country back to deficit-busting policies that forced it into a three-year 78-billion-euro ($83 billion) bailout in 2011.

‘The president of the republic (Anibal Cavaco Silva) decided after hearing from the parties represented in parliament to name Antonio Costa to the post of prime minister,’ his office said in a statement.

Keeping on the government of outgoing conservative prime minister Pedro Passos Coelho ‘would not have served the national interest,’ the statement said.

Although Passos Coelho’s centre-right coalition won the the October 4 election, it lost the absolute majority it had enjoyed since 2011 and his government fell in a parliamentary vote on November 11.

Costa, 54, is a seasoned negotiator who has managed to pull together an alliance that had previously seemed unimaginable due to differences between the groups.

His government’s policies aim at ‘a sustainable reduction in deficits and debt,’ Costa has repeatedly said.

And despite the hostility of some members of the alliance—the communists and the left bloc—to Europe-imposed austerity, a clash between Lisbon and Brussels does not appear to be on the cards.

‘We shouldn’t expect a confrontation because the experience with Greece has shown that this leads nowhere,’ said political commentator Jose Antonio Passos Palmeira.

And despite the political instability, Portugal has still managed to borrow at negative rates in a completely different economic context from when it was forced into a bailout.

Nevertheless, the political situation is far from stable, warned Passos Palmeira.

‘These are fragile alliances which allow Antonio Costa to come to power but does not guarantee a sustainable government,’ he told AFP.

Costa certainly faces a challenge holding together a disparate group—suitable for a man who likes to relax by doing 1,000-piece jigsaw puzzles—but he seems confident.

‘I always deliver more than I promise,’ he declared, pointing to his record as mayor of Lisbon, where he was elected three times, with a bigger majority each time.