Currently, the XACML specification defines a protocol for request / response but leaves it up to interpretation as to how it can be integrated into an enterprise application. I believe that the value of XACML won't be realized unless there is the creation of a new open source project that attempts to develop/standardize around a set of common APIs.
For those who are familiar with XACML, I would love to understand their first reactions to creation of such a project, whether they would be willing to contribute and what they believe an XACML API would look like?