Poland’s president has spoken out against adopting the euro. Lech Kaczynski, in Warsaw, told parliament that, in the current climate, a switch to the single currency would harm the economy.The well-known eurosceptic said government plans to adopt the euro by 2012 would have to be delayed: “The euro is not a cure for all weaknesses. On the contrary, in the global crisis and economic slowdown such a move would be hazardous for Poland.” The devaluation of the zloty is helping Polish exporters, and the president said keeping it would be better in recession. Prime Minister Donald Tusk accepted Kaczynski’s offer to cooperate with the government to fight the crisis. Recession could put criteria for joining the euro further out of reach, but Tusk said that Poland has a good chance of emerging from the crisis without much damage. Insiders saw the exchange as a continuation of the Kaczynski-Tusk feud. Poland’s constitutional court, meanwhile, has ruled on a point of previous contention, saying the president is free to attend European summits, with the prime minister.