Very little of the Politics of Ancelstierre is revealed in the books published so far. The country's political leader is known as the Chief Minister; the only named occupant of this position is Edward Sayre. The parliament of Ancelstierre is referred to as a Moot. Ancelstierre seems to be a parliamentary democracy with a constitutional monarchy.
During the events of Lirael and Abhorsen, Hedge stirs up unrest - perhaps even war - in countries that Ancelstierre borders. This leads to huge immigration of Southerlings, which in turn leads to increased support of a Fascist political party lead by a man named Corolini. During an attempted coup, Corolini's thugs try to assassinate the king and queen of the Old Kingdom.
Corolini's party is the only known political party; the actual policies or opinions of Edward Sayre, or any other politicians, are unknown at this point.