Political Science as the dismal science?

Scottish historian Thomas Carlyle referred to political economy (the original term for economics) as the dismal science in 1849, an expression that has stuck.  However, William Riker a political scientist that works in the area of rational choice theory (the name pol-sci people have for public choice) noted in 1980 that political science is the real dismal science.  One reason for this is simple, in economics we have positive things to discuss, such as voluntary trade being mutually beneficial. In other words, when individuals exchange goods and services both parties are made better off.  In politics however there are winners and losers.  One of the things that public choice economics teach us is that transactions in the political arena unlike the private arena have winners and losers.  I cannot subsidize farmers to make them better off without first taxing some one else and taking resources (income) away from them.  Regulations can often benefit one business at the expense of other businesses or consumers.  Even in elections there are winners and losers.  The examples go on, but maybe we should decide whether Carlyle or Riker got it right.