War and armed conflict — Effects of war — On private contracts — Contract for supply of arms to belligerent State — Arms export embargo by third State — Status of embargo under international law — Whether such legislation is a matter of international public policy — Whether brokerage agreement relating to illegal arms sales enforceable in municipal courts

Economics, trade and finance — Export embargo — Legislative ban on arms sales to belligerent States — Unenforceability of brokerage agreement relating to illegal arms sales — International public policy — The law of Belgium