むずかしくはありません。changeです。何か物足りなく思う人はregime change,alternation of powerとかいえば120点です。
http://www.youtube.com/watch?v=ukN5eyl53oM 0:01 Japanese voters are heading to the polls in a general election that is likely to see the conservative Liberal Democratic Party return to power. 保守的な自民党が政権の座に返り咲く見通しだ。
http://www.youtube.com/watch?v=4WtnIaW40BU 0:47 regime change