Sister Lucia had already given an indication for interpreting the third part of the “secret” in a letter to the Holy Father, dated 12 May 1982:
“The third part of the secret refers to Our Lady’s words: ‘If not [Russia] will spread her errors throughout the world, causing wars and persecutions of the Church. The good will be martyred; the Holy Father will have much to suffer; various nations will be annihilated’ (13-VII-1917).
The third part of the secret is a symbolic revelation, referring to this part of the Message, conditioned by whether we accept or not what the Message itself asks of us: ‘If my requests are heeded, Russia will be converted, and there will be peace; if not, she will spread her errors throughout the world, etc.’.
Since we did not heed this appeal of the Message, we see that it has been fulfilled, Russia has invaded the world with her errors. And if we have not yet seen the complete fulfilment of the final part of this prophecy, we are going towards it little by little with great strides. If we do not reject the path of sin, hatred, revenge, injustice, violations of the rights of the human person, immorality and violence, etc.
And let us not say that it is God who is punishing us in this way; on the contrary it is people themselves who are preparing their own punishment. In his kindness God warns us and calls us to the right path, while respecting the freedom he has given us; hence people are responsible”.
http://www.ewtn.com/fatima/apparitions/Third_Secret/Fatima.htm
It relates to the spread of Communism - the ‘errors’ of Russia. The world breathed a sigh of relief when the Soviet Union collapsed. But now, we see it inside our house (USA). Obama is a harbinger of the cancer among us.
http://www.youtube.com/watch?v=0LHRzxgAxRo&feature=player_embedded#
http://www.youtube.com/watch?v=yGqPo5ofk0s