lsat-4-1-21(lawyer改标题)

21. whenever a major political scandal erupts before an election and voters blame the scandal on all parties about equally, virtually all incumbents, from whatever party, seeking reelection are returned to office. however, when voters blame such a scandal on only one party, incumbents from that party are likely to be defeated by challengers from other parties. the proportion of incumbents who seek reelection is high and remarkably constant from election to election.

if the voters' reactions are guided by a principle, which one of the following principles would best account for the contrast in reactions described above?

请问划线词是什么意思？

还有：

the proportion of incumbents who seek reelection is high and remarkably constant from election to election.

这句话怎么翻译？谢。

1。account for 解释

2。每届再选的现任者比例高且稳定