“For there is no constitutional right for any race to be preferred… If discrimination based on race is constitutionally permissible when those who hold the reins can come up with "compelling" reasons to justify it, then constitutional guarantees acquire an accordion-like quality.”

1960s, Family Planning - A Special and Urgent Concern (1966)

ibid.
Judicial opinions

The Cornerstone Speech (1861)
Context: This idea, though not incorporated in the constitution, was the prevailing idea at that time. The constitution, it is true, secured every essential guarantee to the institution while it should last, and hence no argument can be justly urged against the constitutional guarantees thus secured, because of the common sentiment of the day. Those ideas, however, were fundamentally wrong. They rested upon the assumption of the equality of races. This was an error. It was a sandy foundation, and the government built upon it fell when the 'storm came and the wind blew'.

Popular Government: Its Essence, Its Permanence and Its Perils, chapter 4, p.90 (1913).

As quoted in His Brother's Blood: Speeches and Writings, 1838–64 https://books.google.com/books?id=qMEv8DNXVbIC&pg=PA198 (2004), edited by William Frederick Moore and Jane Ann Moore, pp. 198–199
1860s, Speech to the U.S. House of Representatives (April 1860)

Adarand Constructors, Inc. v. Peña, 515 U.S. 200, 239 (1995) (Scalia, J., concurring).
1990s

As quoted in His Brother's Blood: Speeches and Writings, 1838–64 https://books.google.com/books?id=qMEv8DNXVbIC&pg=PA193&lpg=PA193 (2004), edited by William Frederick Moore and Jane Ann Moore, p. 193
1860s, Speech to the U.S. House of Representatives (April 1860)

Judge Napolitano on Hannity and Colmes http://www.youtube.com/watch?v=bejmEG_t9mI, discussing the Supreme Court rulings on the scope of the protections in the Constitution.
Context: The Constitution applies to persons, not just citizens. If you read the Constitution, its protections are not limited to Americans. And that was written intentionally, because at the time it was written, they didn't know what Native Americans would be. When the post civil war amendments were added, they didn't know how blacks would be considered, because they had a decision of the Supreme Court called Dred Scott, that said blacks are not persons. So in order to make sure the Constitution protected every human being: American, alien; citizen, non-citizen; lawful combatant, enemy combatant; innocent, guilty; those who wish us well, those who wish us ill... they use the broadest possible language, to make it clear: Wherever the government goes, the Constitution goes, and wherever the Constitution goes, the protections that it guarantees restrain the government and requires it to protect those rights.

1920s, Letter to Charles F. Gardner (1924)
Context: Leaving out of consideration the manifest impropriety of the President intruding himself in a local contest for nomination, I was amazed to receive such a letter. During the war 500,000 colored men and boys were called up under the draft, not one of whom sought to evade it. They took their places wherever assigned in defense of the nation of which they are just as truly citizens as are any others. The suggestion of denying any measure of their full political rights to such a great group of our population as the colored people is one which, however it might be received in some other quarters, could not possibly be permitted by one who feels a responsibility for living up to the traditions and maintaining the principles of the Republican Party. Our Constitution guarantees equal rights to all our citizens, without discrimination on account of race or color. I have taken my oath to support that Constitution. It is the source of your rights and my rights. I propose to regard it, and administer it, as the source of the rights of all the people, whatever their belief or race.