"Human kind cannot gain anything without first giving something in return. To obtain, something of equal matter must be lost. That is alchemy's first law of equivalent exchange." - Alphonse Elric, Fullmetal Alchemist.
Even since the Promised Day, Amestris has procured the illusion of Peace. The government was forced to reform due to the events of the Promised Day and the days leading up to it. While staying a Parlimentary Republic, this parliment was no longer a cover for the authoritarian government it was under Fuhrer King Bradley. While the Fuhrer still holds title of Head-of-State and Commander-and-Chief, the Parliment now holds the majority of the government's power. From this change came peace treaties with Drachma in the North as well as Creta in the West, and even Aerugo in the South, and a cooperation and alliance with the country of Xing and their Emporor, Ling Yao.
While it seemed the reform of government happened overnight once the events of the Promised Day had passed, the rebuilding of Ishval had not. This took time, as it was reinstated as a Holy Land. The Amestiran government had a lot to make up for, and it took the combined efforts of General Mustang's team as well as Scar and Major Miles efforts to bring Ishval back to its former glory.
Years passed, and it really seemed that the country was at peace. With the final peace treaty signed with Drachma and the Isvallan rebuilding completed, the next step for the parliment shocked the country. As a way to promote the peace of the land, and as a promise to all peoples who were effected by the Ishvallan Civil War as well as the Promised Day, the Amestrian Government passed a proclemation that they were doing away with the State Alchemists. The so-called Dogs of the Military would be no more, and there would be more regulation of Alchemists throughout the country so as to ensure that there would never be another time like the time around the Promised Day.
This proclamation started as something all had agreed to. The Alchemists knew that it would only be to ensure they followed the rules that they had already agreed to follow when becoming Alchemists. However, many years passed. The regulations on Alchemy got even more strict over the many years of so-called peace in Amestris.
And now, some one hundred or so years since all of this occurred, Alchemists have become the outcasts. They are judged for crimes that happened years before they were born. They are shunned, and the military will find any reason to hastle them for any charge, even if they are not doing anything against the Alchemic Regulation Proclemation, or the ARP. If anything bad ever happens, it is blamed on Alchemists. There are few places left in the country where Alchemists can feel free.
Now Amestris is about to find out just how much they need their Alchemists.