A 1980 analysis by Karlheinz Reif and Hermann Schmitt concluded that European elections were fought on national issues and used by voters to punish their governments mid-term, making European Parliament elections de facto national elections of second rank. This phenomenon is also referred to by some experts as the "punishment traps," wherein voters use the European Parliament elections and other European integration referendums as punishment for governments on account of bad economic performance. There is also a study that showed how voters tend to choose candidates of a party at the European level if it has a history of advancing specific issues that they care about. This is related to the second theory that explains voter behavior and it involves the so-called attitude voting in which voters are assumed to be acting on the basis of their attitude towards the European integration. This is analogous to the American two-party system in the sense that voting on issues and legislation in the Parliament only requires a yes or no vote, which means voter vote for options or candidates that are close to their ideals.