The law, which was passed in October, allowed Mr. Bush to order Terri Schiavo's feeding tube reconnected. Her husband Michael had fought a long court battle to carry out what he said were his wife's wishes not to be kept alive artificially.
Bush, who is supported by the women's parents, Robert and Mary Schindler, filed an immediate appeal of Thursday's ruling that the law is unconstitutional
The Schindlers doubt their daughter, who lives in a nursing home, had any such end-of-life wishes and believe her condition could improve with therapy. She has been in a persistent vegetative state since 1990 when she collapsed from a chemical imbalance.
The narrowly crafted law that allowed Bush to order Schiavo's feedings resume was passed by the Legislature in special session in October specifically to save her life. Six days earlier, her husband had had her feeding tube removed with court permission.
Michael Schiavo's attorney, George Felos, immediately sued Bush, asserting that the law violated Terri Schiavo's right to privacy and separation-of-power provisions of the Florida Constitution.
In fighting that lawsuit, Bush's attorney, Ken Connor, had sought to take depositions from seven witnesses, including Michael Schiavo and the woman with whom he now has a relationship, about issues relating to Terri Schiavo's' care and her end-of-life wishes.
Felos fought that effort, arguing that the issues raised by governor were irrelevant or were already covered when the witnesses testified in previous proceedings. Baird ruled in Felos' favor, but said he might allow depositions later if it was proven necessary.
But an appeals court said in February that Michael Schiavo "failed to demonstrate good cause for a blanket ban on the taking of depositions."