On Saturday, China said that it was suspending all imports of coal from North Korea as part of its effort to implement United Nations Security Council sanctions aimed at stopping the country’s nuclear weapons and ballistic-missile program. The ban, according to a statement posted on the website of the Chinese Commerce Ministry, takes effect on today and will last until the end of the year. While China will hardly suffer material adverse impacts, Chinese trade - and aid - have long been a vital economic crutch for North Korea, and the decision strips North Korea of one of its most important sources of foreign currency.