The Supreme Court will examine Arizona's Immigration Law this week. It is the second major challenge to federal power that the justices have to look at within a month.
Because the state law uses federal definitions on immigration status, Arizona describes it as "cooperative enforcement" of federal law, and says it isn't going against Congress's intent.
The state law requires police to check the immigration status of people they stop if suspicious of their right be in the U.S.
It also makes it a crime for immigrants without work permits to seek employment.
Both of these provisions, among others, have been blocked by federal courts for interfering with federal immigration laws.
The Supreme Court could end up upholding some but not others because each provision must be looked at and analyzed separatly. Justice Elena Kagan, who was solicitor general when the Obama administration filed its challenge to SB 1070 and has recused herself.
The decision is likely to come in the final days of June, the same as the health-care ruling.