The game was getting boring and terrible so the JCP and RPP mutually agreed to dissolve. The JCP split into the Liberal and Labor parties while the RPP became the Whigs and the regional Imperial Bloc. Eventually, the Liberals collapsed for fairly obvious reasons and the Whigs and IB merged to form the Federalists.
This marked the end of an era in Atlasia and was generally agreed to be a good thing. Despite the longstanding myth that Atlasia naturally gravitates toward having two major parties, it's a historical anomaly.
Something is only an anomaly until it becomes not so. It is rather odd that we seem to be right back where we were in 2010 with a few slight differences. The population skews somewhat less leftward overall for one and thus one of the parties is more centrist as opposed to a second leftwing party.
A suspect that a former centrist JCPer taking such a position though is not a surprise.