As I grew up, I advanced in my History classes until I graduated from high school in the year 2013. The problem is, I was only taught about events that happened until one or two years after World War Two. The Cold War was covered in Geography classes more like it was something new, or not yet deeply studied and comprehended by historians. But, when I had classes on the History of the United States, they stopped at Obama's first election. Also, when I had classes about my own country's History, they stopped in the late 1990s. Some other books I've read about various historical subjects always stop at some point between 1960 and 1990. I've noticed a trend in them: they usually stop two or three decades before their writing time. So is that the threshold between History and non-History?
Also, on a somewhat related topic, how much time do historians generally need to be able to write about a topic without politics being involved in it, or at least involved only to a small extent?