Unfortunately, the studies that provide the evidence are pretty decently flawed (as my colleagues have explained above), so until there are more reputable studies I personally won't be changing my mind. NPs may be safe for the routine, run of the mill practice settings. However, I would be very wary of letting full autonomous practice happen. There is no way that you or any NP can say you know medicine to the depth that MD/DOs do. Given that, there are always uncommon presentations of diseases, rare diseases, etc that an NP would have a much higher chance to miss. If NPs wanna run the minute clinic, go for it, but opening up your own offices is bad news waiting to happen. If doctors get sued as much as they do, lawyers will have a field day with NPs purely based on education discrepancy alone.
NPs are not stupid people by any means, and nobody is insinuating that they are. NPs simply cannot compare to knowledge level of doctors. Thats the truth and there is no arguing that fact. Another thing is that NPs practicing on their own also requires them to take full malpractice insurance, which some people I have heard just want the full practice rights without being close to the liability.
Basically, my point comes down to this. If you want to be a doctor, go to medical school. There is no way NPs should be full autonomous practice except in actually rural areas (most new NPs are taking jobs in cities like the rest of us). It may be "safe" for the bread and butter cases, but once something dire hits, I don't really trust their knowledge base. I've seen the NP curriculum, and it simply doesn't compare in the slightest