“Don’t twist the lion’s tail.” This warning was issued by one of Argentina’s most powerful trade union leaders, Luis Barrionuevo, this week. It was directed at the government led by President Mauricio Macri. “Those who attacked the unions – the military, [Raúl] Alfonsín [1983-1989] and [Fernando] de la Rúa [1999-2001] didn’t finish their terms,” Barrionuevo added in case the message was lost on Macri. Barrionuevo spoke out in the wake of an unprecedented surge in arrests of union leaders accused of corruption as battle lines are drawn ahead of a congressional debate of the most important piece of legislation the government wants to see approved in 2018: a sweeping labour reform designed to improve Argentina’s competitiveness, and diminish the power and influence of the unions.