O'Reilly said the growing threat of ISIS reminds him of the time before the 9/11 attacks.
He pointed out this week's foiled plot in Boston as the latest indication that ISIS-inspired terror could kill Americans.
"ISIS is a threat to every single American. Somebody tell President Obama," O'Reilly remarked in his Talking Points Memo.
O'Reilly said the U.S. and NATO should have destroyed ISIS a long time ago, but the West lacks "the will to protect their populations."
It's a lot like al Qaeda before the 9/11 attack. Back then, U.S. intelligence knew al Qaeda was growing in strength and training people in Afghanistan for terrorist missions. We knew that and we did little," said O'Reilly.
Now that ISIS is spreading in the Middle East and using social media to encourage attacks, he called it "just a matter of time" before an ISIS-inspired attack happens here.