In personam jurisdiction.

It is legal jurisdiction over the person. It occurs when:

1: You are present in the jurisdiction and properly served.

2: You are domiciled in the Jurisdiction

3: You consent to Jurisdiction

4: You have minim contacts with the Jurisdiction.

I Don't remember exactly the case but if you're a citizen, the Federal Government has jurisdiction over you at all times regardless of where you are located. I believe it falls under the consent provision. You consent by being a citizen. Now this only applies to certain laws, such as the trading with the enemy's act, which the Cuban embargo falls under now. That's why pre-trading with the enemy act, you could bring back something like 5 Cuban cigars purchased overseas without a problem. Now it's totally illegal.