TRENTON, N.J. (AP) — A wounded Chris Christie is working to move beyond the most challenging test of his political career, while the New Jersey Republican governor's critics promise to keep probing a traffic scandal that rocked his administration this week and threatens to tarnish his national image ahead of the next presidential contest. [...] after documents revealed Wednesday that his administration may have intentionally caused the traffic jam to exact political retribution, the governor fired a top aide and jettisoned his chief political adviser. Christie adamantly denied any personal "knowledge or involvement" in the lane closures, a passionate pronouncement that satisfied some critics in the short term but creates political risk amid ongoing investigations. Stepien had widely been seen as a potential campaign manager for Christie if he runs for president and had been tapped to serve as a senior political aide on the Republican Governors Association, which Christie will lead for the next year. Political strategists suggested the episode offers future opponents a readymade line of attack — who likes a traffic jam?