It's a matter of public record that this particular echelon of the profession donates more to Democrats than Republicans, by a significant margin...as does the profession as a whole.
A lot of the attorneys that the Trump administration folks have retained are also significant D donors. Hell, Trump's lead attorney has donated to some very prominent left-leaning D's.
What this means to me is that, while it doesn't guarantee a lack of bias, it at least indicates that they have been able to do their jobs without bias and adhere to the ethical standards of their profession in the course of reaching that level of professional success. Is it always going to work that way? Probably not. Does it, generally? Yes.