Last week, with little notice, a federal judge here tossed out Delta Air Lines’ longstanding claim that the government’s export credit agency — which, among other things, provides loan guarantees to overseas airlines for the purchase of Boeing jets — was helping international competitors at the airline’s expense.

Delta offered only a shrug. Judicial opinions aside, the continued existence of the Export-Import Bank turns more on bare-knuckle politics than on legal niceties. MORE