US Ambassador to Pakistan Cameron Munter announced to his staff Monday morning that he was stepping down this summer after serving less than two years on the job.We’re told his early departure — ambassadors usually serve three-year tours and Munter has only been in Islamabad since October 2010 — is not related to any particular policy dispute, either with the administration or the Pakistanis.There was a bit of tension all around, however, in March 2011 when a drone strike killed 44 people and wounded 50 more in North Waziristan. The attack came the day after former CIA contractor Raymond Davis was released and left the country after being detained for shooting and killing two Pakistanis.Word is that Munter, a veteran career diplomat whose prior postings had been in Bonn, Prague and Warsaw and as ambassador to Serbia before becoming a senior official in Iraq in 2009 and 2010, simply wasn’t a good fit with the Pakistani government — and perhaps not with the Obama administration as well