This prophecy talks about a plan by Islam to take over and subjugate America for Mohammed and Islam in general and eventually turn it into an Islamic nation. This includes making threats to influence congressional decisions, forcing its way into school systems by demanding time to pray, plans to have a president in the Whitehouse by 2024 (It's not speaking of Obama, or even a closet Muslim like him, but rather a future person who will be a full blood, in your face, dyed in the wool, openly Islamic Muslim man), and taking control of multiple large cities making them entirely Islamic.
But is only the tip of the iceberg on all the prophecies which speak of the Islamization of America. The plans are much, much bigger and broader than this. The prophecies don't specifically say that Islam will succeed in turning the nation entirely Islamic, but they will have some success in infiltrating our nation and subjugating it which will eventually lead to its future conquering (see "The Destruction of America" prophecy) and removal as a nation. And while Islam will do much to weaken America, it will ultimately be forces other than Islam that will bring it down, even though Islam will play a large part in that destruction.
EDIT (2021-11-03): We're far enough into this, especially with the recent and HUGE influx of Muslims into the nation, that we're at the point of this being fulfilled. That doesn't mean God won't reverse it. It just means that America has been Islamisized. No, we're not a Muslim nation, and never will be. Nor does the prophecy say we will become that way. However, enough of Islam has entered into, and poisoned this land, that I'm classifying this as fulfilled.
(*Do you have a better description, or did you find an error? Please let me know.