As long as people still continue to have different beliefs, there is bound to be terrorism.
Terrorism cannot be eliminated unless every single person in the world has the same beliefs and there is nothing to fight about. There will always be conflict until the world becomes a single, Utopian society.
How do we protect ourselves against the next 9/11? It will be bigger and it will most likely be more bloody.
The men and women of the US intelligence agencies are working their butts off to protect you and me from the next attack often to the detriment of their own families, they work tirelessly to protect ours.
After hundreds of billions of dollars spent on homeland security, America clearly is safer and more aware of the threats surrounding it. Likewise, the U.S. military, the CIA, and the FBI have eliminated most of the terror leadership in recent years, diminishing its operational capacity through relentless drone strikes and captures.
Let's take a look at two possibilities that might be used in the next terror attack.
The Lone Wolf
They are hiding among us. They hide in plain sight by disguising themselves. They carry American or European passports. They can hide bombs in all sorts of places, in plain sight. It's the sick ambitions of a caliphate bent on carnage which we need to be on the lookout for.
Terrorism has also now been monetized. ISIS have become an employment agency for anyone wanting to join their convoluted society. Lone wolves or sleeper cells, they all get paid to continue their beliefs against the West. They run brothles with free wives, tagerting Yazidi women and rape has become an ideal in some cirles. For some, this is the Utopia.
However, the lone wolf attacks, inspired by ISIS, is something that can happen at anytime, anywhere.
So, what can America do to protect itself? We need to continue our focus on human intelligence (HUMINT). Both from an infiltration persepective by using informants and by initiatives recently launched by Homeland Security, "If you See something, Say something."
The EMPW
A further threat than a mass sleeper cell or lone wolf attack is the detonation of an atomic warhead, not physically on US soil, but about 25 miles up in the air called an Electro Magnetic Pulse Weapon (EMPW). Should a detonation like this happen, it will darken America triggering a series of electromagnetic pulses, frying everything electronic. You can just imagine the chaos it will create. No electricity, no celllphone towers in operation, no computers working. It sounds like Armageddon, but the likelyhood of plunging America back to the dark ages is there.
At least we can be comforted by the fact that the Government is speding billions of dollars within the intelligence industry to gather info that will deter these type of attacks. If that means that I need to give up some of my privacy so that they can listen to conversations of citizens, I am willing to give that up.
The men and women protecting the borders of the US, give up way more.

Terror Plots Plotted against the USA recently