An excellent post indeed. And an interesting one as well. I am probably biased since my entire medical experience has involved working with NPs and PAs. From my undergrad research in heart failure, to my work as a trauma tech in the ER, to my medical training in Years 3 and 4 of medical school they have always been a part of how I have seen medicine done and it has always been a very positive and fruitful experience.
Yes, there are going to be "bad" ones who go outside their scope, who don't know or recognize their limitations, who are too arrogant to ask for help, or whatever. But those sorts of physicians also exist. In fact, one anecdote is that during my time in the ICU the PA I worked with was honestly at LEAST as good as most of the attending physicians.
The key, I think, is to recognize the fact that many conditions have become routine. Particularly in outpatient medicine, most of what we see is pretty rote and straightforward and there is honestly no reason to have the vastly excess amount of education and training we have in order to manage those sorts of patients. As my step-father (a critical care physician for a few decades now) likes to say, 80% of medical conditions can be diagnosed and treated by the ladies at the hair salon. We train for so long and learn so much to make sure and catch that 20% that doesn't quite fit. The point being that there is absolutely no reason NPs (or PAs) can't handle the majority of cases within a specific field. As Dr. Gorski pointed out, it is the foolhardy physician that overestimates his or her abilities and doesn't call for help when needed. In fact, in my medical education it was drilled into our heads that the first step of any emergency is "call for help." And they know they are training physicians here.
I think an important part of it - and really the only way that patient safety could actually be endangered (well, moreso than physician care) - is to make sure that the APRNs/PAs actually have access to help should they need it. But that is true for any practitioner of course.
Obviously, since the education is less broad in scope than our own and the training less, it is also necessary (IMHO) to specialize up front... which they already do. I mean honestly, I have zero interest in pediatrics. In fact the most common thing I heard on my pediatrics rotation was "That is absolutely correct... for an adult." Yet I had to rotate through it, do pediatric surgery, and my board exams all have pediatrics on them (Steps 1, 2, and 3 of the USMLE - not my subsequent specialist boards). Why? So I can be more comprehensive and have flexibility in where I want to go with my career. But if I already knew I wanted to do pediatrics, why not just go directly that route? In the new era of medicine - which is, absolutely and unequivocally a team effort - it makes perfect sense to have people with less overall education and training but with just as much (if not more) in a specific field of medicine. I think medical school and physician training are great for people who want more comprehensive education and abilities or who are just unsure of where they want to go with their careers. Having an opportunity to sample all the different fields of medicine is highly valuable. But if I run into a kid on the streets in severe medical distress my first action will be to call for help, then do general stabilizing and temporizing measures, and then get that kid to someone who knows how to do medicine on children!
There could be the argument that giving APRNs independent practice rights could jeopardize patient care. Horse hockey. That argument is like saying that the existence of urgent care centers jeopardize patient care because they aren't full ED's. It is the responsibility of the urgent care to refer and act rapidly as necessary and it would be the same responsibility for independently practicing NPs. Just as my license will be on the line if I don't act in accordance with my own practice limitations, so will theirs.
In an inpatient setting, I think it may be possible for APRNs to act independently in low acuity setting but I would be hard pressed to think it makes sense in a critical care setting (though I am very open to being convinced otherwise). That said, they make invaluable assets to critical care teams and I have thoroughly enjoyed working with them in those settings. It is amazingly wonderful to be able to kick around ideas and discuss patient care plans with someone who actually understands what you are saying. And to then be able to delegate tasks in order to make workflow go better is awesome. If I don't have time to place a central line I know the PA/NP can do it for me and we can get more patient care done and focus on the real meat of medicine rather than the procedural stuff which just takes up time. You do not need to be a physician to place a central line. Yes, complications happen. But if I caused a pneumothorax or induced ventricular tachycardia from placing a line I would still call for help as well. There's no room for cowboys in medicine anymore, no matter what your training and education.
Sorry for the rambling comment. Been putting it together in between doing other tasks. Basically I wanted to lend my support as a newly minted physician for advanced practitioners (or mid-level practitioners, whatever term is better/more favored/less offensive). They will prove to be an invaluable asset in providing good quality care at all levels. The only real trick will be ensuring that their education, training, scope, etc are defined and done well... but that goes the same for physicians as well.
I am starting to get the feeling that our profession is becoming more and more irrelevant. With fools like this, there will be literally NO reason to go to medical school and do a residency (that is, unless you want to spend half a million $ just to "sample more" of what is out there 
)
