TO AVOID the dynasties that have misruled many Latin American countries, Guatemala’s constitution forbids relatives of the incumbent president and vice-president from running for high office. This clause had seemed to scotch the chances of Sandra Torres, the country’s ambitious first lady, becoming its first presidenta. But on March 21st she and her husband, Álvaro Colom, announced a novel way to sidestep the rules: they filed for divorce.

Rather than being a sign of marital discord, the parting looks much more likely to have sprung from political unity. Speaking last month, Mr Colom gushed over his wife’s leadership skills and the “impressive passion” she inspired. On March 8th Ms Torres declared that she would run as the candidate of National Unity of Hope (UNE), her husband’s party. Candidates can register from May 2nd, and the election will be held in September.

Ms Torres’s eligibility is still in doubt. The constitution excludes the president’s blood relatives up to his cousins, and his in-laws up to grandparents and grandchildren. But there is no mention of exes, leaving the question up to the Constitutional Court. Its five members were chosen this month and will be seated in April.

Ms Torres is not the only candidate running on dubious constitutional grounds. Álvaro Arzú, a former president, is campaigning despite a ban on re-election. Zury Ríos, a congresswoman, may be blocked by a prohibition on the relatives of the organisers of coups, since her father, Efraín Ríos Montt, toppled a government in 1982 and installed himself as dictator. Eduardo Suger, another possible candidate, was born in Switzerland and may not meet the requirement to be “Guatemalan in origin”. “Ministers of religion” are forbidden from running too, which might spell problems for Harold Caballeros, the founder of a large evangelical church.

One of the few candidates free of constitutional entanglements is Otto Pérez Molina, a former general who narrowly lost a run-off vote to Mr Colom in 2007. Mr Pérez Molina is the strong favourite: a recent poll put his support at 43%, with Ms Torres next on only 11%. In 2007 he promised an “iron fist” against crime. Since then Guatemala has become far more dangerous, as Mexican cocaine smugglers have put down roots in the wild jungle areas near the northern border. After four years of the soft-spoken Mr Colom, some Guatemalans might fancy an ex-army man to drive the gunmen back across the frontier.

Ms Torres, on the other hand, has strong support in the countryside, where the social programmes she directs have had the biggest impact. Mi Familia Progresa (My Family Progresses), a conditional-cash-transfer scheme, has improved the lot of poor indigenous women, who may fear the consequences of Mr Pérez Molina’s hard line on crime. The concentration of Ms Torres’s backers in rural areas means that pollsters, who do not always venture into Mayan mountain villages, probably underestimate her strength.

It is too soon to make reliable forecasts about the election. The field is likely to be crowded—14 candidates, mostly from fairly new parties, stood in 2007—and the dynamics of a run-off depend on who squeaks through the first round. At the moment, many candidates are content to focus on getting on the ballot.