Mainly, that this is a dangerous idea:

---480G

I thought terrorism was already illegal. No?

---AngelaMotorman

Not domestic terrorism.

---480G

But isn't that kinda like: pasta is illegal. Let's make macaroni n cheese illegal too! ??

---code_archeologist

It is a jurisdictional problem.

When a crime is committed in Texas it is within the jurisdiction of Texas State investigators, but not within federal jurisdiction unless the law broken is also a federal crime, the criminal is a foreign national, or the crime crossed state lines.

So most of the domestic terrorist attacks are staying inside a single state's jurisdiction, and the FBI is only acting in a consulting role. As a result if there is a network of domestic terror cells, the FBI has not been able to run the investigation across state lines to identify such, or collect data that would allow them to identify markers in order to interdict domestic terror.

A later reply in the chain reads:

---kin_of_rumplefor

So why not U.S. soil = federal grounds. My mind is kind of blown that domestic terrorism isn’t considered a federal offense.

--- Jasrek

Because then every crime would be a federal crime and states would surrender their law enforcement authority for local crimes.