We began our next unit on political parties by defining what constitutes a political party and by tracing how our two party system evolved. We then addressed the function and role of third parties such as the The Green Party and the Libertarian Party. I noted how third parties can alter presidential elections as they did n in 1990 for George Bush due to Ross Perot's candidacy and as they did in 2000 for Al Gore due to Ralph Nader's candidacy. Last, we sutured how some third parties fade when the party's leader retires. However, certain ideological parties, such s the Green Patrty, tend to survive .