Man of Lawlessness
2 Now we request you, brethren, with regard to the coming of our Lord Jesus Christ and our gathering together to Him, 2 that you not be quickly shaken from your composure or be disturbed either by a spirit or a message or a letter as if from us, to the effect that the day of the Lord has come. 3 Let no one in any way deceive you, for it will not come unless the apostasy comes first, and the man of lawlessness is revealed, the son of destruction, 4 who opposes and exalts himself above every so-called god or object of worship, so that he takes his seat in the temple of God, displaying himself as being God. 5 Do you not remember that while I was still with you, I was telling you these things? 6 And you know what restrains him now, so that in his time he will be revealed. 7 For the mystery of lawlessness is already at work; only he who now restrains will do so until he is taken out of the way.
The passage that you have quoted raises the most difficult question for any would-be prophecy analyst to explain.
What “lawlessness” was already in place when this passage was written (presumably before the end of the first century A.D.) and who was then restraining it, and continues to restrain it until some modern or post-modern time when he no longer restrains it?
This would seem to disqualify almost every modern political or religious creed, if it applies to the earth. If it pertains to the heavenly places, then we are left in the dark about how to interpret the passage. We are in position to judge what lawlessness might be restrained in some other place than the earth.
I may be wrong about this interpretation; the “now” may refer to a time ahead of the writing of the prophecy as the prophet is shown some future time. Then it could mean something like Putin is the man of sin but restrained until Medvedev is taken out of the way (this is just an example, not what I would think is the most obvious verification).
In any case, for a literal fulfilment, a man of sin needs to enter some holy place (a temple) and declare himself to be God. There was some interest in Obama as this figure in part beause he acted that way, but only in a vaguely similar way, there was (to the best of my knowledge) no event where Obama actually entered a temple and declared himself to be God.
Even Hitler or Stalin never quite did something like that. But other historical figures have. And the world did not end when they did so.
This introduces what I call the principle of prophetic selection — just because conditions for fulfilment exist in the world does not mean God will activate the end time events at that moment. He then has to review the situation and choose whether or not to act. So even by studying the signs we can never be sure.