Why was united states v. lopez (1995) important? it was the first time since the new deal that the supreme court limited the power of congress outlined under the commerce clause. it was the first time that the court had used the tenth amendment to limit the power of congress. the court found that citizens could not bring racial discrimination suits against state governments. the court found the line-item veto unconstitutional. the court gave a broad interpretation of the commerce clause that expanded the power of the federal government over the states?