This is an interesting choice of words by the Apostle Paul in 2Thes. 2:11, to further explain His teachings. What was written almost 2,000 years ago, is the circumstances that is a reality in 2013. People were confused about the times, and chain of events, concerning the return, of our Lord, and Savior, Christ Jesus.
Christ Jesus returns to the earth, on the 7th. Trump period. 666, comes before 777. Christ fills in the details in His Word. Paul further simplifies the Truth. 2Thes. 2:9 is "key" to all of the mess. This is the "beast" that is the one-world-political-system, spoken of in Rev.13.
The children of Cain, wicked leaders of the blind, and the uninformed are pushing the agenda. Paul reverences "Strong Delusion" = this is a stupor. a slumber. confusion; IE: drunkard stupor. Some have it for protection-others have voluntarily sought this condition.
The Word states that for those that have rejected the "love of the Truth, that they might be saved", would receive "Strong Delusion". This condition is one step away from the walking dead, or zombie status. This is a hard saying and ruff words; what can be worse?
Many leaders, beginning with families through large groups are in a stupor, already operating under "Strong Delusion", and require others to follow them-this is sad. Christ states "He that is Not with me, is against Me; he that gather[eth]Not with Me *Scatter[eth]".