Submitting yourself for security clearances involves signing up for these investigations. Either he did so and regrets it, or he took a job that absolutely requires that he did, but he didn't.
It also creates a scenario where people remain on the bench long after their competence has likely faded. RBG, for instance, was 87 years old when she 'retired.' Her final wish is to not be replaced until a new President had been sworn in, which was predictably not granted. She had 30 years to choose that presidency herself, but simply refused to do so.