European Union defense ministers adopted a plan Monday to open up their $35 billion arms industry to increased cross-border competition within the 25-nation bloc _ a landmark move designed to cut costs for tight military budgets. The new “code of conduct” is voluntary and nonbinding, but it marks a breakthrough after decades efforts to persuade nations to relax the protection of their tightly guarded national defense markets and allow Europe’s defense companies to compete on a continentwide level. Full Story