For the mystery of iniquity doth already work: only he who now letteth will let , until he be taken out of the way. 2 Thessalonians 2:7, KJV
For the secret power of lawlessness is already at work ; but the one who now holds it back will continue to do so till he is taken out of the way. 2 Thessalonians 2:7, NIV
Both versions of this passage are posted so that we may compare the language. I believe that the term "letteth" might be confusing to some, especially the young.
Who is the "he" that restrains evil today, but will not in the future? There are two main understandings of who "he" is. One is that the restrainer of evil is the Holy Spirit acting in the world. A second is that he is the Holy Spirit in the church.
The second view is consistent with the "salt of the earth" spoken of by Jesus, where his people keep the world preserved. Does this now apply to the church?
Either way, whoever the restrainer is, he will be taken away allowing full reign of the Devil.
Paul speaks of the Rapture of the church as being a turning point for the whole world. A historical illustration would be to compare Europe before and after Constantine's Edict of Toleration. As the church--corrupt as it was--became more of an influence, Europe became more stable.
Who of us does not see the church losing influence? Could it be that this restraint is being gradually withdrawn, to be fulfilled with our complete absence?
Israel, as a nation, failed. The church as an institution, is failing. But the elect of both Israel and the church will be saved.
A crumbling world will dramatically come under the full influence and power as the Great Tribulation unfolds. The King and his bride will celebrate the marriage supper of the Lamb, as Israel's last judgement takes place.