A more common approach has been for mainstream parties to openly attack the populists and construct a "cordon sanitaire" to prevent them from gaining political office Once populists are in political office in liberal democracies, the judiciary can play a key role in blocking some of their more illiberal policies, as has been the case in Slovakia and Poland. The mainstream media can play an important role in blocking populist growth; in a country like Germany, the mainstream media is for instant resolutely anti-populist, opposing populist groups whether left or right.