third rail

US /ˌθɜːrd ˈreɪl/
UK /ˌθɜːrd ˈreɪl/
"third rail" picture
1.

第三轨, 敏感问题

a political issue that is so controversial that any politician who dares to broach the topic will suffer a backlash from voters

:
Healthcare reform has become a third rail issue in American politics.
医疗改革已成为美国政治中的一个第三轨问题。
No politician wants to touch the third rail of social security.
没有政客愿意触碰社会保障的第三轨