to block arizona's tough new law, the federal government argues immigration is its jurisdiction. the suit says, a state may not establish its own immigration policy or enforce state laws in a matter that interferes with the federal immigration laws. arizona's governor says the state is stepping in where the feds have failed. >> we need the federal government to do their job. and if they don't do it, then arizona will. >> our senior legal analyst says the issue of federal jurisdiction is the main basis for the government's lawsuit. >> most of what we discussed about the law is, is it profiling, is it discriminatory about -- against hispanics? that's not the claim. at least by the federal government in this litigation. what they are saying is that under the constitution, this area of law, immigration, is reserved for the federal government. and states have no right to pass laws because that is -- they