I would like to read current moral philosophers who take similar positions on moral obligation as those taken by G. E. M. Anscombe in Modern Moral Philosophy.
Her view, as I understand it, is that moral obligation is inadequately grounded without either a divine law and legislator or a philosophy of psychology replacing that divine law and legislator. Furthermore, an adequate philosophy of psychology does not exist and so one should give up on justifying moral obligation and return to an ethics similar to that developed by Aristotle.
Her paper was written in 1958. Since that time I imagine others have continued with similar views, but I don't know who they are. This is mainly a reference request to philosophers working today who take similar views on moral obligation that she took.
Anscombe, G. E. M. (1958). Modern moral philosophy. Philosophy, 33(124), 1-19. https://www.pitt.edu/~mthompso/readings/mmp.pdf