Richard II is most definitely a political play - When reading it, one must consider themes like the merits of keeping a bad ruler in office (the anointed king) and whether or not it's better for a country to continue with the status quo, or to make changes.  And although we're talking about medieval English history with this play, those themes of rulers and the good of the country still resonate today, particularly during this election year in America.

Check this link for various themes about Richard II:

http://www.enotes.com/richard-ii/themes