Best "Because it was unconstitutional according to the 14th Amendment."
Explanation:
It's also true that President Ford felt Executive Order 9066 had been unjust, but it was not "a piece of legislation." It was an executive order issued in 1942 by President Franklin Delano Roosevelt, which denied equal rights to American citizens of Japanese ancestry. Section 1 of the 14th Amendment reads as follows:
All persons born or naturalized in the United States and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.
Here (from the Gerald R. Ford Presidential Library & Museum) is the full text of what Pres. Ford said in rescinding Executive Order 9066:
In this Bicentennial Year, we are commemorating the anniversary dates of many great events in American history. An honest reckoning, however, must include a recognition of our national mistakes as well as our national achievements. Learning from our mistakes is not pleasant, but as a great philosopher once admonished, we must do so if we want to avoid repeating them.
February 19th is the anniversary of a sad day in American history. It was on that date in 1942, in the midst of the response to the hostilities that began on December 7, 1941, that Executive Order 9066 was issued, subsequently enforced by the criminal penalties of a statute enacted March 21, 1942, resulting in the uprooting of loyal Americans. Over one hundred thousand persons of Japanese ancestry were removed from their homes, detained in special camps, and eventually relocated.
The tremendous effort by the War Relocation Authority and concerned Americans for the welfare of these Japanese-Americans may add perspective to that story, but it does not erase the setback to fundamental American principles. Fortunately, the Japanese-American community in Hawaii was spared the indignities suffered by those on our mainland.
We now know what we should have known then--not only was that evacuation wrong, but Japanese-Americans were and are loyal Americans. On the battlefield and at home, Japanese-Americans -- names like Hamada, Mitsumori, Marimoto, Noguchi, Yamasaki, Kido, Munemori and Miyamura -- have been and continue to be written in our history for the sacrifices and the contributions they have made to the well-being and security of this, our common Nation.
The Executive order that was issued on February 19, 1942, was for the sole purpose of prosecuting the war with the Axis Powers, and ceased to be effective with the end of those hostilities. Because there was no formal statement of its termination, however, there is concern among many Japanese-Americans that there may yet be some life in that obsolete document. I think it appropriate, in this our Bicentennial Year, to remove all doubts on that matter, and to make clear our commitment in the future.
NOW, THEREFORE, I, GERALD R. FORD, President of the United States of America, do hereby proclaim that all authority conferred by Executive Order 9066 terminated upon the issuance of Proclamation 2714, which formally proclaimed the cessation of hostilities of World War II on December 31, 1946.
I call upon the American people to affirm with me this American Promise -- that we have learned from the tragedy of that long-ago experience forever to treasure liberty and justice for each individual American, and resolve that this kind of action shall never again be repeated.
