[Excerpt] State measures that would deny or provide access to public institutions of higher education, instate tuition, and financial aid to unlawfully present aliens have been challenged on various grounds. While these grounds can vary depending upon the specific statute or practice in question, the grounds most commonly asserted appear to be violations of the Equal Protection and Supremacy Clauses of the U.S. Constitution. Thus, these provisions are the focus of discussion in this report, and the following paragraphs provide an overview of the basic principles implicated in discussions of equal protection and preemption.