Well, I can agree that the US is perceived as a threat, and if there were no US, then NATO/Europe wouldn't be perceived as threatening to Russia, because it would simply be too weak. On the other hand, I know Russian people genuinely who feel, and know people with more Russian contacts than I who'd concur, that the threat starts at the geographical interface between Russia and western europe. Even though they don't intellectually believe NATO tanks will come rolling over their border in the foreseeable, they have a gut level unease, and would be much happier with a buffer of Russian-dominated, or at least neutral, states between them and 'the west', notably including the USA.