You are absolutely right. We could never count on any of the justices appointed by republican presidents to vote to overturn it.
If our government is such that the citizenry is incapable of protecting the most innocent and vulnerable of its fellow Americans through the political process put forward by the Founding Fathers, then the flaw in the nation's founding is such that it's not worth saving.
Is that "heresy" here? Probably. But we should all keep in mind that there were never any promises made as to where this experiment in democracy was going to end up; Benjamin Franklin was pretty clear that the Republic would only survive "if (we) could keep it".