Costa Ricans will choose a new president April 1, and the decision will have important implications for trade. Presidential candidate Carlos Alvarado of the ruling center-left Citizen's Action Party (PAC) opposes joining South American free trade bloc the Pacific Alliance, while Fabricio Alvarado of the conservative National Renewal Party (PRN) supports joining it. The disagreement boils down the impact joining would have on a key domestic constituency: farmers....