An interesting idea, flipping 9/11 on its head, so to speak, and all of world history with it.
This book tries to be two things: the alternative history and a thriller.
The alternative history gets boring rather quickly, which is a shame, since all the details surely took a lot of work. USA→USA, bomb throwing radical Muslim Arab terrorists → bomb throwing radical Christian European terrorists &c. &c.
The thriller part, in the part that i managed to read, was OK, if you like that kind of thing. Only, i don’t, really. Good cops chase bomb throwing terrorist, one of the cops goes in alone “Leeee-rooy Jeeeenkiiins!!!” style and it works.

P.S. 1: Well, maybe there are some SciFi-ish plots twist later, but i got bored before i got there.
P.S. 2: I did read another “What if”-novel with The West not the dominant power, [b:The Years of Rice and Salt|41143|The Years of Rice and Salt|Kim Stanley Robinson|https://d.gr-assets.com/books/1328745220s/41143.jpg|74882], which is longer, and long-winding, but that one i finished.