Josh Marshall is against Obama keeping Gates:
...consider it from this perspective. If Barack Obama is elected president in November it will be for many reasons. But preeminent among them will be the American people's desire to decisively turn the page on the disastrous foreign policy -- in all its permutations -- of the Bush years, a foreign policy that has been characterized by belligerence and in the most direct sense by war, and one in which the Pentagon has played a dominant role, often at the expense of the Department of State. Elected on those terms, I simply do not see how an incoming President Obama can choose to keep on the man who ran the Pentagon on behalf of President Bush and executed his policies, regardless of the man's qualifications in the abstract.
Because under Gates, those policies were restrained and sanity restored to the Pentagon. Because Gates represented a willingness to confront reality after fantasy. Because in the testing period of a new president, a defense secretary already ensconced and deeply competent would be a great asset. Because Obama seeks both to turn over a new leaf - but also to unite.