Some discriminatory laws were written in a way that, at least theoretically, applied to both blacks and whites.

Virginia’s anti-miscegenation law forbidding interracial marriage banned marriage between “a white person and a colored person.” Mildred and Richard Loving challenged the law, arguing that it violated the Equal Protection and Due Process clauses of the 14th Amendment. The case eventually made it’s way to the United States Supreme Court. In [Loving v. Virginia] (http://www.law.cornell.edu/supremecourt/text/388/1), Virginia argued the statute was constitutional because it applied equally to both races because it barred both whites and “colored persons” from interracial marriage.

the State argues that the meaning of the Equal Protection Clause, as illuminated by the statements of the Framers, is only that state penal laws containing an interracial element as part of the definition of the offense must apply equally to whites and Negroes in the sense that members of each race are punished to the same degree. Thus, the State contends that, because its miscegenation statutes punish equally both the white and the Negro participants in an interracial marriage, these statutes, despite their reliance on racial classifications, do not constitute an invidious discrimination based upon race.

The Court wasn't buying what Virginia was selling because, despite the alleged color-blindness of the law, it only barred marriage involving a white person. There was no bar against intermarriage between other races.

There is patently no legitimate overriding purpose independent of invidious racial discrimination which justifies this classification. The fact that Virginia prohibits only interracial marriages involving white persons demonstrates that the racial classifications must stand on their own justification, as measures designed to maintain White Supremacy. We have consistently denied the constitutionality of measures which restrict the rights of citizens on account of race.

Although the way Virginia wrote the law may seem to be an obvious attempt to get around the 14th Amendment, it had at least one case supporting its position. A 19th century Supreme Court case had accepted Virginia’s “equal application” argument, although for a law about adultery rather than marriage. But the Supreme Court had previously rejected the reasoning of that case and reiterated that it was no longer a valid theory.

The State finds support for its "equal application" theory in the decision of the Court in Pace v. Alabama, 106 U.S. 583 (1883). In that case, the Court upheld a conviction under an Alabama statute forbidding adultery or fornication between a white person and a Negro which imposed a greater penalty than that of a statute proscribing similar conduct by members of the same race. The Court reasoned that the statute could not be said to discriminate against Negroes because the punishment for each participant in the offense was the same. However, as recently as the 1964 Term, in rejecting the reasoning of that case, we stated "Pace represents a limited view of the Equal Protection Clause which has not withstood analysis in the subsequent decisions of this Court."

Even though the “equal application” theory was shot down, both Pace v. Alabama and Loving v. Virginia show that at least some discriminatory laws were written in such a way that the states could use the “gee, we’re not discriminating against blacks because the law also punishes whites” argument.

Having rejected the “equal application” argument, the Supreme Court went on to hold that anti-miscegenation laws violate both the Due Process and Equal Protection clauses of the 14th Amendment.

Marriage is one of the "basic civil rights of man," fundamental to our very existence and survival … To deny this fundamental freedom on so unsupportable a basis as the racial classifications embodied in these statutes, classifications so directly subversive of the principle of equality at the heart of the Fourteenth Amendment, is surely to deprive all the State's citizens of liberty without due process of law. The Fourteenth Amendment requires that the freedom of choice to marry not be restricted by invidious racial discriminations. Under our Constitution, the freedom to marry, or not marry, a person of another race resides with the individual, and cannot be infringed by the State.

Aside from the constitutional issues, the story of the Lovings, their relationship, marriage and court case is a beautiful and heartbreaking story. They are largely forgotten Civil Rights heroes but every June 12 (the anniversary of the decision in Loving v. Virginia) people celebrate Loving Day.

Follow up: would there be any reason to prefer black versions of things (I.e. drinking fountains, etc...?)

Plessy V. Ferguson was the court case that ruled segregation to be constitutional, probably a case you've heard of if you grew up in the US. A man who was 7/8 white, 1/8 black was removed from the white only section of a passenger train and arrested due to a Louisiana law saying that races must be separated in train cars. He appealed his case and it made it to the Supreme Court. They ruled that it was constitutional for states to make segregation laws. In the Majority Opinion of the case Judge Brown says:

Laws permitting, and even requiring, their separation in places where they are liable to be brought into contact do not necessarily imply the inferiority of either race to the other, and have been generally, if not universally, recognized as within the competency of the state legislatures in the exercise of their police power.

Whenever segregation is mentioned the emphasis is on separation of the two races. There might be more relevant quotes in the ruling or a different case that answers the question more specifically but, in theory this means that whites couldn't drink at the same water fountain as blacks. I don't know if the law was enforced on whites, but I doubt whites were really interested in breaking that law. Here is the text of the ruling if anyone's intersted.

There was a great documentary called "The Durrs of Montgomery" ( http://www.aptv.org/docs/detail.asp?DocID=4) that discussed how Bull Connors was about to arrest an integrated meeting for worker's rights in Birmingham unless they segregated. The separated into two sides of the auditorium seating. Eleanor Roosevelt, who was opposed to segregation, sat on the black side. Bull Connors threatened her with arrest. She moved to sit right on the dividing line painted down the aisle. Connors backed down, but technically she was breaking the law.

I know of at least one instance where a jazz hall was blacks only; whites were not allowed inside but instead had to listen from the street. Good Hope Hall in Lafayette, La:

In the roaring twenties and the depression of the thirties, Good Hope Hall became one of the truly great jazz halls of America as all of the great jazz artists from across the country played there regularly. Included in this list of impressive figures in the early days of jazz were Louie Armstrong and Fats Pinchon. It also was the center for orchestras and bands from all over Louisiana, as well as out-of-state touring bands of great repute. Tradition has it that whenever a dance was scheduled for Good Hope Hall that evening, the trumpeter of the jazz band to play there would climb to the upper gallery of the structure, blow his horn for several minutes and thereby announce to the entire community in the downtown area some blocks away that things would be lively that evening at Good Hope Hall. When those evenings came around, the African-American community in the Mouton Addition entered their meeting hall, Good Hope Hall, and enjoyed the jazz music in raucous dance and merriment while many members of the Caucasian community gathered outside in the streets to listen to the superb strands of jazz music filtering out from within. Perhaps in all America, this was the only corner in the 1920's and 1930's where African-Americans were the only ones permitted inside while the white community was left out in the street. ^[1]

Other References: 1 2

Wasn't Rosa Parks sitting in the black section of the bus and asked to move farther back so a white person could sit there? Couldn't this indicate that whites were allowed and actually expected to sit in the black section, presumably as long as blacks sat farther back? Or would this indicate that the definition of the black section was dynamic and could change at the whim of white people?

I was familiar with some of the interracial laws, but overall, very interesting responses!