You're correct about this being a global phenomenon. All countries face this, and as Mr. Linklater mentioned, for example, the Arab Spring that happened not long ago posed certain challenges to all border authorities around the world, certainly to those in Europe.
The way you have to prevent terrorists from slipping through the net goes along with what I was talking about last week—working with our key allies, having a robust prevention strategy that operates overseas, and sharing information appropriately with key allies. Oftentimes, it comes down to very strong intelligence work.
Then, should a mass arrival happen at your border, what we've learned from the MV Sun Sea and MV Ocean Lady is the key aspect that Mr. Hill just talked about—ensuring that the border authorities have the time to do the proper checks, and the time to go out and work with their international colleagues to exchange information, if necessary, to help establish identity and admissibility.