Before we attempt to answer this "simple" question, we should all be clear on the definition of "nation". According the Mr. Webster, a "nation" may be defined as "a territorial division containing a body of people of one or more nationalities and usually characterized by relatively large size and independent status". So how many "nations" are there in the world?
Well, certainly the nations that have membership in the U.N. qualify as nations - that makes between 190 and 200 nations worldwide. But this is most definitely not the answer - not anymore. So lets list the other types of "nations" in the world today - organized bodies of people with territories, cultures containing their own moral standards, and the profound allegiance of their members.
Tribes in the sense of "primitive peoples" living in remote areas or developed areas but attempting to retain their own cultures.
Criminal organizations: Various "Mafia"; Yakuza; Triads and Tongs; Posses; Syndicates; Drug Cartels; Street Gangs; and Biker Gangs. All of these fit the definition of nations given above.
Terrorist Organizations or Militias (or "Freedom Fighter" depending on your own viewpoint).
And... the most rapidly growing group of nations that are becoming more powerful every day in the U.S. - Big International Businesses.
The bottom line is that there are a hell of a lot more independent nations currently operating in the world than are seated at the U.N. and many of these are far more powerful in every sense than the majority of Nations holding seats in the U.N. All of these organizations do not owe allegiance to the formal nation that they exist in. Drug cartels are not worried about the people living in Colombia or Mexico etc. Biker gangs are not concerned about the harm their meth labs do to the people inhabiting the State or Country they reside in. And large corporations couldn't care less about the well being of the population that resides in the Country they have their Corporate headquarters in. Their allegiance is only to the Organization. Their culture (think about the meaning of terms like "Code of the Mafia" or "Corporate Culture") dictates the way they think and supplies a rationale for everything they do. So we now live in a Nation that is being ruled by other nations with different cultures, different goals, and an utter disregard for the rest of the people residing within the borders of the U.S. Most of these other nations are two-class societies - a small number of exceedingly wealthy people at the top and large numbers of unimportant foot soldiers or workers below. This is why an ostensibly "American Company" has no hesitation about shipping jobs overseas and putting "fellow Americans" out of work. There's nothing wrong with that - the Company is just adhering to the most important cultural norms - its own. It's why there is no hesitation about exploiting or discarding its workers - its culture in only concerned with short-term gain and the "bottom line." Health care? You'll be able to afford your own health care if you reach the top - if not, you don't deserve it. Health care for people who don't even belong in your nation? Don't be silly - when was the last time you thought about health care for people living in Mongolia?
So we've been quietly invaded and taken over by a large number of nations that do not give a damn about the well-being of the U.S. - just their own top echelons. They've bought our Congress and Presidency and by doing so, the Supreme Court. So far, the Supreme Court has just ruled that they enjoy the same rights as people in terms of campaign contributions but the fact is that they have been above the law as it applies to the rest of the U.S. citizenry for a long time. Get caught with an ounce of marijuana and you're looking at jail time. Almost bring down the economy after a vast series of con games that you had to have known would ultimately do exactly what they did and you're still getting multi-million dollar bonuses courtesy of a population of fools who live in another nation and aren't any of your concern. Education? For the important members of your nation - of course. For anyone else - definitely not. It's easier to fool an ignorant/uneducated electorate - just give them issues you don't care about like 2nd Amendment fears, evolution, abortion, DADT, flag burning and the placement of the 10 Commandments in courtrooms. If those fools think that those issues are the most important ones that affect heir lives and the lives of their children, they'll overlook those you'd rather not have discussed - like growing income inequality, the exportation of all manufacturing and the rise of utterly incompetent and ignorant potential "leaders". And it's easy to do - just make education unaffordable and buy your own media (but be sure to call it "fair and balanced").
Welcome to the new world. Anyone have suggestions on turning things around?