Economists emphasize the welfare gains of unrestricted trade, but politicians worry about the income distribution effects of increased competition. We show that the welfare gains of a trade shock become ambiguous if inaccurate information hinders optimal income redistribution with distortionary policy instruments. To be sure about the net welfare outcome of a compensated trade shock, the government must know the size of the trade shock and the corresponding size of the policy instrument that is needed to generate a balanced budget. If this is not the case, politicians may have a point when being hesitant about the gains from trade. (C) 2013 Elsevier B.V. All rights reserved.