#8 Counterintelligence is forever.
Hostile foreign intelligence services represent persistent threats. Nation-state adversaries generally don’t go away or give up, even if regimes change. For example, the FBI has been dealing with intelligence threats from the Soviet Union and the Russian Federation since 1917. The FBI will be dealing with the intelligence threat from China for as long as it exists. To be sure, the clandestine intelligence activities of foreign powers change over time depending upon the needs of the country and developments in fields such as science and technology, politics, and the economy. So counterintelligence officials must be adaptive and creative over an extended period. - Lawfare