"... the first successful use of ESCs destroys the opposition." Well, that's an astonishing bit of hyperbole! Kind of like saying, 'the first person kept from dying by eating fellow survivors of a plane crash on a remote mountain and everyone will start eating their neighbors.' Opposition to ripping the fetal stem cells from embryos doesn't fair or fall based on what the liberals can say about the person debating the issues or upon one man's way of phrasing the argument. Even if one 'trial' has found success, the entire methodology is cannibalism. Does that change when one success is rigged up?
No, it's not. Once ESCs are used successfully to treat something, the lid is off. The argument moves to whether or not you want to "deny this life-restoring treatment" just to save a "mass of undifferentiated cells." That argument ought to sound awfully familiar to you -- it's the same one used to justify abortion.