The Supreme Court has rejected an appeal challenging campaign disclosure laws in Washington state.

The court on Tuesday let stand without comment a federal appeals court ruling that upheld the state's disclosure requirements. Human Life of Washington challenged the requirements as a violation of the First Amendment. The group didn't want to reveal its donors in a 2008 campaign opposing an assisted suicide ballot measure.

The San Francisco-based 9th U.S. Circuit Court of Appeals said the disclosure requirements "have become an important part of our First Amendment tradition."