Thread:Bluerock/@comment-44626702-20191208220655/@comment-1504072-20191209181542

Hey, no need to overthink things. The simplest answer can be found by looking at MGS1's story by itself.

In MGS1, the Pentagon ("Patriots") had become suspicious of the behavior of FOX-HOUND and the genome army, prior to the Metal Gear test exercise. On the day of that exercise they had some of the troops replaced, one of them being Meryl. Therefore, in the event that a rebellion occurred, Meryl's presence could be used to manipulate Campbell, in order to ultimately recruit Solid Snake to deal with the incident. The Pentagon also wanted to secure Metal Gear's test data.

We later learn that this data was indeed secured, albeit by the U.S. President himself via the spy Ocelot.

Now, in MGS2, it is actually revealed that President Sears acted independently, sparking the terrorist incident himself via Ocelot, his own agent, in order to recover the data. However, his actions ended up revealing the existence of both REX and the Genome army, which did not suit the Patriots' plans.

In summary, the Pentagon/Patriots suddenly feared for the loss of their secretly-developed weapon at Shadow Moses, and made plans to retrieve it should the worst happen, while the terrorist incident itself was instigated by President Sears in an act of rebellion.


 * As for why Sears rebelled against the Patriots, he likely saw an opportunity at Shadow Moses to weaken them, by denying the U.S. Government the Metal Gear test data. His ultimate motivation for destroying their power are elaborated on in MGS2.