His failure to convict Republicans and Democrats alike show this is not a partisan take. His unanimous loss in the Robert F. McDonnell hearing before SCOTUS earned him a firm reprimand before the same court. He is overzealous and seems to have some rather fanciful interpretations of the law. I'm sure he has a fine reputation among the "get Trump" crowd, but who else?
I realize that Garland probably saw Smith as an expendable attack dog. If Smith got caught tampering with evidence or misleading the court about it (
he did) well, that's on him and nothing you can blame Garland for, right? In any case, Smith is not someone you want if you are seriously trying to get a conviction of a powerful person. Had Trump lost the election, one could argue that the investigation and indictment would have fulfilled its true purpose.