Radio messages which are divorced from the local supporting evidence and background are believed to have relatively little effect on primitive societies. The local government of an underdeveloped country is likely to be far more effective in its propaganda than remote outsiders. In more advanced societies, where propaganda might be more effective, the scope for counter measures is likely to be greater, too.
With satellites the ability of a country to defend itself against intruding broadcasts is greater than with conventional broadcasting. In addition to the possibility of jamming, there is the possibility (for the major powers at least) of silencing or even destroying the offending satellite without violating the territory of the state from which the original transmission is coming.