The FINANCIAL -- As Republicans take the stage in Cleveland for their first presidential primary debate tonight — with Donald Trump in the middle of it — one thing is already abundantly clear: A lot of voters are angry. Very angry. In fact, a lot of voters have been angry for some time. The phenomenon that we call “negative partisanship,” antipathy on the part of Democratic and Republican voters toward the opposing party and its leaders, has been on the rise since the 1980s, and today it is arguably the most salient feature of the political scene in the United States. Now voter ire appears to be shaping both parties’ 2016 presidential nomination races. The rise of Trump and Bernie Sanders in the Republican and Democratic nomination contests, respectively, is symptomatic of this increased anger in the American electorate.