Development: On 29 April the constitutional chamber of El Salvador's supreme justice court (CSJ)ordered the supreme electoral tribunal (TSE) to cancel the legal status of two of the oldest parties, the centre-right Partido Demócrata Cristiano (PDC) and Partido de Conciliación Nacional (PCN).

Significance: The ruling overturns a contentious legislative decree from 2005 (586) which had allowed the PDC and PCN, which have a total of 12 seats in the 84-seat congress, to remain in existence, even though they failed to win the necessary 3% of the vote in the (last but one) 2004 presidential election. Given that both the PCN and PDC had positioned themselves as right-wing alternatives to the previously ruling Alianza Republicana Nacionalista (Arena,1989-2009) and although the PCN has also been an ally of Arena in the past, the ruling should benefit Arena's main right-wing rival, the Gran Alianza por la Unidad Nacional (Gana), which has 16 seats.

Key points:

• The CSJ's ruling declared unconstitutional Decree 586, which had invoked Article 85 of the constitution, which states that the party system is "pluralist". The court also ruled that that it was unconstitutional to legislate retroactively.

• Civil society groups such as the local NGO Iniciativa Social para la Democracia (ISD) have hailed the court's ruling as a step forward for the democratic political party system.

• The CSJ said that if the PDC, which was formed in 1960, and the PCN, which came into being the following year, are to compete in the 2012 municipal and legislative elections they must collect 50,000 signatures and meet all the necessary requirements imposed on new political parties. Given the tight time frame, they are unlikely to achieve this for the 11 March 2012 election. This will leave just the ruling left-wing Farabundo Martí para la Liberación Nacional (FMLN), Arena, Gana and the moderate left Cambio Democrático to campaign.