Florida's so-called right-to-die law allows courts to consider testimony about the wishes of someone on life support if the person left no written directive.
Lawyers for the husband, Michael Schiavo, said that argument flouted the state's right-to-die law.
Instead, the right-to-die law, passed as a ballot initiative by 51 percent of the voters, went into suspended animation as opponents took their case to the courts.
Missouri's right-to-die law requires "clear and compelling" evidence of a patient's wishes.
The case posed the first major test of Connecticut's right-to-die law when her family fought to disconnect her from a life-sustaining feeding tube.
Missouri has one of the most restrictive right-to-die laws in the nation.
California introduced auto emission standards, a Conservation Corps, a pioneering right-to-die law.
The state already has one of the strictest right-to-die laws in the country, requiring elaborate proof of a patient's wishes before life-support equipment can be withdrawn.
New York, she said, already has one of the strictest right-to-die laws in the country.
But he noted that the status of right-to-die laws was by no means clear.