Ammendments to the ADA were 20 years in the making and now only a year after they go into effect there is a bill in Congress to start chipping away at them via enforcement funding. Those changes were in part to reinstate some Civil Rights of persons with disabilities that were taken away through decisions of the Supreme Court.
As you know, any decision of interpretation of law made by the Supreme Court is final so Congress had to in essence put into place a new law and this is not always something quick to happen ~ here it took 20 years.
The other way to make a major impact on a law is by taking away funding to enforce that law. People can get up and wave their arms around and make verbal threats all they want as we often see when someone claims foul to the treatment they have received in a Public Access dispute. Without the Dept. of Justice actually stepping up and agreeing to act on a violation then it is hard to enforce someone's Civil Rights.
A fear of some in the SD community is over the current risk to the funding of the DOJ which allows them to enforce the section on Miniature Horses. This action is perceived by some as a chilling glimpse of how quickly funding could be taken from enforcement of Public Access Rights of handlers using SDs.
In looking into the matter, it can make it somewhat easier to keep in mind that the DOJ stated that only dogs can be service animals. Public Access Rights were also in part given to handlers of miniature horses but their standing was not given the same status as dogs. Miniature horses due to a strong lobbying effort were given a placement but in somewhat more of a grey area full of uncertainty of how that placement would play out. We are beginning to see that their placement was not as firm and clear cut as the stronger DOJ placement of dogs. In my opinion, if the Dept. wanted to give equal status they would have made the service animal definition more on the lines of "Service animal means any dog or miniature horse that is individually trained to do work or perform tasks ..."
You can research this bill via the Library of Congress
Bill Summary & Status ~112th Congress (2011 - 2012) ~ H.R.5326
Bill Summary & Status - 112th Congress (2011 - 2012) - H.R.5326 - THOMAS (Library of Congress)
Assistance Dog Advocacy Project (ADAP) - Non-Profit Organization - Interlachen, FL | Facebook