Ignore the rulings. Federal rulings do not trump state constitutional amendments. WI’s amendment was upheld by the state Supremes. Walker should have told Crabb to go to Hell.
Reasonably sure that question was argued and settled at Appomattox Courthouse in Virginia in 1865 by a Mr. Lee and Mr. Grant with the outcome being in favor of the supremacy of the federal government.
This is actually addressed in the US Constitution.
This Constitution, and the Laws of the United States which shall be made in pursuance thereof; and all treaties made, or which shall be made, under the authority of the United States, shall be the supreme law of the land; and the judges in every state shall be bound thereby, anything in the constitution or laws of any state to the contrary notwithstanding.