No one has a clue what the future holds.

Those that tell you otherwise are selling something

Linton Wells (wiki link) is an expert in national security and served in a number of different roles in the White House under both Bill Clinton and George W. Bush.

As the Deputy Assistant Secretary of Defense to President Bush, Wells published a memo titled “Thoughts for the 2001 Quadrennial Defense Review.”

Note: I actually found the document.

The memo reads:

If you had been a security policy-maker in the world’s greatest power in 1900, you would have been a Brit, looking warily at your age-old enemy, France.

By 1910, you would be allied with France and your enemy would be Germany.

By 1920, World War I would have been fought and won, and you’d be engaged in a naval arms race with your erstwhile allies, the US and Japan.

By 1930, naval arms limitation treaties were in effect, the Great Depression was underway, and the defense planning standard said, “no war for ten years.”

Nine years later, World War II had begun.

By 1950, Britain no longer the world’s greatest power, the Atomic Age had dawned, and a “police action” was underway in Korea.