Not necessarily true. Public media can be subverted by the state (which usually is the one that gets to fund this type of media), making them vulnerable to exactly the type of propaganda that the Eastern Roman empire inflicted upon Romans. I would argue instead that the key to securing a nation is to have well educated populace that is equitably engaged with the political process without fear or intimidation. A free public square starts with a free, wise public, not media. Media is merely a tool to facilitate the discourse.