Is Kant a moral constructivist or a moral realist?

The dominant interpretation of Kant as a moral constructivist has recently come under sustained philosophical attack by those defending a moral realist reading of Kant. In light of this, should we read Kant as endorsing moral constructivism or moral realism? In answering this question we encounter disagreement in regard to two key independence claims. First, the independence of the value of persons from the moral law (an independence that is rejected) and second, the independence of the content and authority of the moral law from actual acts of willing on behalf of those bound by that law (an independence that is upheld). The resulting position, which is called not 'all the way down' constructivism, is attributed to Kant.