[miker]

The US Government consists of three, equal, but separate branches. The Executive Branch, the Legislative Branch and the Judicial Branch.

The HSCA is in the Legislative Branch.
The DOJ is the Judical Branch.

Each branch of government can change acts of the other branches.

In this case the HSCA issued a report in 1979. In their report they asked the Judicial Branch to check their work by conducting their own study.

In 1988, the Judicial Branch closed the case and in so doing stated that their is no evidence of a conspiracy.

That is the last word, so far, on this case.

The worst case scenario: it is not clear what is the official stance of the U.S. Government. Since the Legislative Branch asked the Judicial Branch to review their work and the Judicial Branch has issued the last word on this case, I would assume that the official stance of the U.S. Government is that there was no conspiracy in the assassination of John F. Kennedy.