A recent federal case in Washington D.C. illustrates a distinction between the IDEA and Section 504. As a brief background, the case was brought by the parent of a girl with special needs against the District of Columbia, D.C.'s then-mayor Adrian Fenty, and D.C.'s then-schools-chancellor Michelle Rhee under both the IDEA and Section 504. The parent alleged that the district failed to properly identify her daughter's issues in a timely manner and failed to provide the right educational support. She claimed that Section 504 requires "substantial procedural compliance with all procedural and substantive rights under the IDEA" and that the district had violated both the IDEA and Section 504 by failing to provide FAPE, failing to properly evaluate the child, and failing to provide an appropriate IEP and placement. It seems like the parent just lumped those two pieces of law together and, as described below, the district court stepped in with some clarification on the issue.
In this case, Holmes-Ramsey vs. District of Columbia (D.C. District Court, November 2, 2010), the court said that in order to state a claim under Section 504, the parent has to show that the child was discriminated against solely because of her handicap. BUT, in order to make out a Section 504 claim in the context of an IDEA case, the parent must show that the district acted in bad faith or with gross misjudgement. It's not exactly clear what would make it an "IDEA case" per se. But in such a case, it is not enough just to show a failure to provide a FAPE under the IDEA. You need to show something more than that to make out your 504 claim. One might say: "If anyone who has protections under the IDEA has the same protections under Section 504, it should be enough just to show a violation of IDEA to make out your 504 claim." Unfortunately it doesn't work that way. The correct way to think about it is that the IDEA is made up in part by Section 504 and in part by other stuff, and showing a violation of "FAPE," for example, which is guaranteed under the IDEA but not under Section 504, is not necessarily a violation of Section 504. Section 504 is a discrimination statute intended to protect individuals with disabilities being treated differently because of their disabilities. But it doesn't say anything about ensuring that a child with a disability will get an educational program that is specially designed to meet his/her unique educational needs -- that's the IDEA's job.