Its the federal laws that are unconstitutional.
Kansas has the power to uphold the US constitution.
Federal acts which are unconstitutional are not laws. If the Constitution is the supreme Law of the Land, then by definition there can be no laws which contradict it. Maybe I'm a broken record, but I really wish conservatives would remove the oxymoronic phrase "unconstitutional law" from their vocabulary, and refer to unconstitutional legislation as the XXX Act or XXX Statute, rather than dignifying it with the undeserved title "XXX Law".