That's easy. In the Schiavo case, all Jeb Bush would have had to do was sit down and write a couple of paragraphs invoking his executive power and duty as the Governor of the State of Florida to enforce Article One, Section Two of the state's constitution. Two troopers deliver the order to the hospice, and bada bing, Terri would still be with her family today. By the way, I had a long conversation with the LEO officers in front of the hospice, and asked them explicitly about this. They made it clear that they would have obeyed such an order instantaneously.
In Romney's case, he used his executive power to enforce an unlawful and unconstitutional edict from four out-of-control judges to implement gay marriage. The legislature ignored the court, effectively checking them, but Romney caved, joining the court in checking the legislature. The result? Gay marriage, even though there is still no law authorizing it. All Romney had to do was NOTHING, and there isn't a thing the court could have done about it. If he had, gay marriage would not be in effect in MA.