Federal prosecutors yesterday abandoned an espionage-law case against two former lobbyists for a pro-Israel advocacy group, a case that had transfixed much of official Washington because of its potential to criminalize the exchange of sensitive information among journalists, lobbyists and policy analysts. In asking a judge to dismiss charges against Steven J. Rosen and Keith Weissman, formerly of the American Israel Public Affairs Committee, or AIPAC, officials said recent court rulings had changed the legal landscape and made it unlikely that they would win
