Donald Trump was demanding $400 million from Columbia University.

When he did not get his way, he stormed out of a meeting with university trustees and later publicly castigated the university president as “a dummy” and “a total moron.”

That drama dates back 25 years.

Today, these two New York City institutions — the billionaire president of the United States and the 270-year-old Ivy League university that has cultivated 87 Nobel laureates — have been locked in an extraordinary…