Comment from a reader on Senators Who Kicked Out Bases Wanted Cash: It was a combination of a lot of things...Why did they leave? Depends who you ask. I saw this online. In 1991 increasing Philippine nationalism was leading to the US bases there being very unpopular. Opposition politicians saw opposing the continued US military presence as a vote winner. The US was not unaware of this and had already been looking at other alternatives. The catalyst that made it all happen was the eruption of Mt Pinatubo. This eruption, the largest anywhere in the world in the 20th century, was devastating to the local area, and completely buried in ash the two largest US bases in the country - Clark Air force Base and Subic Bay Naval Base. This forced the evacuation of most US personnel from the country. The Philippines senate pounced and cancelled the leases on both bases. The US simultaneously relinquished its hold on the bases. And the locals likely saw gold in the bases, the vast nature of the acreage there, the infrastructure, the tourism possibilities, etc etc.