AFTER a fortnight of Christmas fiestas, Mexicans groggily returned to work two weeks ago. Or rather, most of them did. For the 500 deputies and 128 senators of the national Congress, the holidays roll on until February. Mexico's lawmakers sit for only 195 days a year, the fewest among Latin America's bigger countries. (Their $11,200-a-month pay, however, is the highest after Brazil's.) When they do stir themselves to vote, it is more often to block rivals' bills than to pass reforms.

Gridlock in the palace of San Lázaro partly explains why Felipe Calderón's presidency, which ends in December, now looks like a six-year damp squib. Mr Calderón has identified many of Mexico's bottlenecks. But most of his big proposals have floundered in Congress. A modest fiscal reform passed in 2007 was eased along only by an electoral law to help the opposition. Last year a competition law tentatively prodded the country's mighty monopolies. But changes to the backward energy sector in 2008 were diluted beyond recognition. A reform of the political system has been similarly gutted and is yet to pass. And there is still no sign of a promised law to improve competition in telecoms.

Even where there is consensus, Congress contrives to disagree. All the main parties say they want to merge the 2,000-plus local police forces, which are helpless before the country's drug mafias. But five years into the war on organised crime, the relevant laws have not passed. In 2010 Mr Calderón proposed a labour reform making hiring and firing easier. The Institutional Revolutionary Party (PRI), the biggest opposition group, rejected it, only to produce a similar plan itself last year. But in December Congress delayed all labour bills indefinitely. The same month, it approved three counsellors to the electoral authority, 14 months late. Earlier, confirming a Supreme Court judge took 15 months.

The Senate has been the less obstructive chamber. Mr Calderón's conservative National Action Party (PAN) is its biggest force, and the Senate leaders of the PRI and leftist Party of the Democratic Revolution (PRD) are more reformist than their counterparts in the lower house. There, many PRI legislators owe political debts to Enrique Peña Nieto, their presidential candidate, who does not want to give the PAN any victories before the July poll. The PRD candidate, Andrés Manuel López Obrador, also has a base in the lower house.

Co-operation has been especially rocky since 2009, when the PAN attacked the PRI in mid-term elections. The mood soured further when the PAN formed a brief electoral alliance with its ideological opposites, the PRD, to push the PRI out of some governorships. With this deal, “the president cancelled the possibility of working according to agreement and consensus,” says Heliodoro Díaz, a PRI congressman.

Such rivalries exist in any democracy. Yet “in Latin America, [Mexico's Congress] stands out as a bad performer,” says Víctor Lapuente, a political scientist at Gothenburg University in Sweden. Unsurprisingly, there has been more conflict since one-party rule ended in 1997. No president has had a legislative majority since then. But Brazil's leaders have coped under worse conditions: neither Luiz Inácio Lula da Silva nor Fernando Henrique Cardoso ever controlled more than 20% of Congress.

Building coalitions is harder in Mexico, where congressmen are wedded to their parties and hard to buy off. No politician, from president to mayor, may stand for consecutive re-election. This quirk means that politicians depend on party bosses, not voters, for their next job, making it essential to toe the party line. (Mr Calderón's political reform included re-election, but was crushed in Congress.)

Voters are unusually loyal too. Mr Lapuente and José Fernández-Albertos, of the Institute of Public Goods and Policies in Madrid, found that in Brazil parties often do well in presidential elections but badly in simultaneous congressional races, or vice versa. In contrast, in Mexico they tend to register near-identical levels of support, as voters rarely split their ballots. This link gives lawmakers every incentive to scupper the president's agenda.

The July 1st elections will completely renew both houses of Congress as well as the presidency. Mr Peña's boosters say that if the PRI wins all three—it already has most state governors—the deadlock will end at last. PRI lawmakers insist they will stop blocking legislation only if Mr Peña wins. “There will be labour reform after the elections of July 2012, when we have a president identified with the principles of the revolution,” Armando Neyra, a PRI congressman, said in December.

Others doubt that Mr Peña will be so revolutionary. He recognises that the oil industry needs foreign private investment, which the PRI has blocked. But many a president has buckled before the mighty oil-workers' union. Mr Peña turned against the labour reform after unions complained. He has befriended the teachers' union, the biggest of all (as did Mr Calderón). And he has been given friendly coverage by Televisa, a TV giant eager to protect its dominant position. Mexico's future is uncertain, but its legislators will have plenty of time to ponder it during their summer holiday—which begins in April.

CORRECTION: This article initially said that Mexico's Congress had the second-shortest working year among Latin America's larger countries. In fact it is the shortest. Details can be found here.