Plans by the Argentine President for an unpopular tax rise have been defeated by her own Vice-President.
The debate to ratify a hefty increase in export tax on soya beans was close.
After a marathon session in the senate, Julio Cobos chose to defy the government. His casting vote broke the deadlock.
Farmers had led a vigorous campaign against the new tax levels for four months. They were jubilant with the result but Cobos described it as the most difficult day of his life.
His boss, the centre-left president Cristina Fernandez, had wanted to benefit more from the country’s soya bean bonanza, and the current high prices on the world’s markets. But now she might have to withdraw an executive order she had used to impose the tax rise.
Soya is Argentina’s leading crop, having become hugely popular with farmers since genetically- modified strains were introduced in the 1990s.
Most is sold abroad and the government had wanted to change the current 35 percent tax on exports to 47 percent.