[Windflier]

Stupid writing, what is a Rust Belt?

It's a well known phrase. Surprised you're unfamiliar with it.

Rust Belt: "Rust Belt" is a derogatory term for an informal region of the United States that experienced industrial decline starting around 1980. It is made up mostly of places in the Midwest and Great Lakes, though definitions vary.

[Political Junkie Too]

It's called the "rust belt" because of its dependence on the steel industry and the decay that resulted from its decline and impacts on downline manufacturing.

-PJ