Google search uses HTTPS and, unless you personally is a target and/or your devices are hacked, the content of your searches is not visible to anyone except Google. Your citizenship doesn't matter.
They've tapped into google's internal networks in the past. I suspect they've already regained the access.
Another matter is whether google really deletes accounts when asked, or really doesn't store histories when asked. Because if the data is stored by Google, when the time comes and the person becomes "interesting" for the US establishment, they can rubber-stamp FISA court warrant and get this data.
1. Google engineers took the challenge personally and there is no evidence suggesting Prisma capabilities were regained. 2.I tend to agree in a sense that it is rather difficult to delete all the data. But no more difficult, than to find it later when requested by law enforcement.
Another matter is whether google really deletes accounts when asked, or really doesn't store histories when asked. Because if the data is stored by Google, when the time comes and the person becomes "interesting" for the US establishment, they can rubber-stamp FISA court warrant and get this data.