WASHINGTON (Reuters) - President Barack Obama's first year in office was marked by creeping mistrust between the White House and the Pentagon over Afghan war policy, with repeated requests for more troops fueling the suspicions, retired General Stanley McChrystal said in a new book. McChrystal, who became the top U.S. commander in Afghanistan during those months, said Obama was elected at a time when General David McKiernan, then head of international forces, was seeking 30,000 more troops to stave off a Taliban resurgence, a request that had been on hold since the previous summer. ...