Port security: A couple of different views of reality

The headline sums it up: Chertoff, Democrats disagree over cargo scans:

Mr. Chertoff said U.S. and foreign officials soon will conduct some screening at the ship's point of departure, but the answer did not satisfy Mr. DeFazio.
"We retain the right of sovereignty in international trade and we can refuse the entry of any cargo," said the Oregon Democrat. "The Chinese regularly do this for commercial purposes; we can sure as heck do it for homeland security purposes.
"Anybody who isn't cooperating with us, we say, 'Well, that's fine, but guess what? Nothing's leaving your port to the United States of America anymore.' It's pretty simple."
Such action, Mr. Chertoff said, would cut off 75 percent of international trade and lead to a depressed economy.
Mr. DeFazio proposed a three-year period to implement such a strategy, but Mr. Chertoff balked and called it an "artificial deadline" that would be "as unrealistic as passing a law that says in three years cancer has to be cured."