Forts are the way to go

The Following was posted on Game News on October 22, 2014. I missed this important update because for some reason it didn't appear on the Forum like other game updates do.I had to scour game updates to find it. Here is what it says:

42. "Military Bases, military airports and fortifications [ top ]
The number of military bases in a country used to depend on the numbers of weapons and military units.
The rules became confusing when players started trading in military bases and were limited in their trading policies by the size of their own army.

We have now simplified the system and removed the dependency on the size of the army.
A country can order a max number of 100 military bases or military airports of each type. When the number is reached, manual orders for military bases and airports will be prohibited.
However, corporations that contract such bases and military airports or fortifications to the countr

Is the GM deliberately misleading and confusing players or is the GM simply inept? Maybe both. Under the war documentation page, click "war documents" and finally select "war features" you will find this regarding forts:

37. "Defensive fortifications [ top ]
Defensive fortifications should be positioned mainly along the borders of the country or as a defense of specific targets. The fortifications are targets that must be destroyed by an enemy if he wants to win a war.
Each fortification represents 0.5 war index points and these points are considered lost if the country does not have these fortifications. If your country has only 20 fortifications, the war index will never exceed 60.

The more fortifications there are, the more complex the war becomes for your enemy. It takes time to mount attacks and with many fortifications, attacks may take a long time to complete which gives the defense more time to r

You answered your own question in the first sentence. It's unlimited.

1400 is a lot but it could be a lot worse. There was a feature once that I don't think works anymore that allowed a player to order many thousands of a product to artificially inflate ones war index

His point is the misleading information in the War Documentation pages... Which everyone knows are misleading anyway. Expect the unexpected, to an extent.