Hungary’s Peter Magyar took his oath of office on Saturday to become the country’s new prime minister, ending Viktor Orban’s 16 years of autocratic rule. Magyar’s centre-right Tisza party defeated Orban’s nationalist-populist Fidesz in a stunning blow last month, gaining more votes and seats in Parliament than any other party in Hungary’s post-Communist history. The win, which gave Tisza a two-thirds parliamentary majority, will allow it to roll back many of the policies that gave Orban a...