This is in part a way for Trump to pursue his goal of reviving the American coal industry. Coal is a 19th century technology. At its peak it was used for heati

This is in part a way for Trump to pursue his goal of reviving the American coal industry. Coal is a 19th century technology. At its peak it was used for heating, steel-making, electricity, and transportation with trains and steam boats. In the 20th century it got replaced by diesel for transportation, greatly reduced for steel-making with the continuous casting process, and gradually replaced in heating by natural gas and electricity. More recently it is getting replaced in electricity generation by natural gas and renewables. You know, if you want your economy to be strong, you need to keep up with new technologies, instead of trying to hang on as long as possible to old, obsolete ones.