hot potato

A problem that is so controversial or sensitive that those handling it risk unpleasant consequences: gun control—a political hot potato.

A problem so controversial and sensitive that it is risky to deal with. For example, Gun control is a political hot potato. This term, dating from the mid-1800s, alludes to the only slightly older expression drop like a hot potato, meaning "to abandon something or someone quickly" (lest one be burned). The idiom alludes to the fact that cooked potatoes retain considerable heat because they contain a lot of water.

The noun has one meaning:

Meaning #1: a difficult situation