The ACLU and Lambda Legal challenged the Nebraska constitutional amendment that excludes same-sex couples from any kind of legal protection for their relationships--from marriage through domestic partnerships. In April of 2003 three advocacy organizations filed suit arguing that the amendment violates the federal constitution because it effectively prevents them from lobbying for any form of relationship recognition for gay, lesbian, and bisexual people in Nebraska, while straight people can still lobby for a variety of protections for their relationships. The advocacy organizations are Citizens For Equal Protection (CFEP), Nebraska Advocates for Justice and Equality (NAJE), and ACLU Nebraska.
https://www.aclu.org/other/citizens-equal-protection-v-bruning-case-profile