When the program fails, someone who said it's a bad idea will be in a good position to explain so. By contrast, someone who worked to "water down" the program will not be in a position to do anything but shoulder blame.
Unfortunately, in California we have a confused bunch in the GOP. In 2003, Gray Davis proposed borrowing $8 billion to address a cash shortfall for operating expenses. Republicans strongly opposed it and took him to court to stop him.
Fast forward... Davis recalled.... Schwarzenegger elected. Schwarzenegger replaces Davis' borrowing scheme with one of his own--borrowing $15 billion for operating expenses. He initiated it, promoted it, and got the CA GOP to endorse it.
It seems that even liberal ideas are embraced by this party, as long as they have an (R) next to them.