[flamefront]

From an 16 Sep. 2001 UK observer article and no doubt to be found in congressional reports:

What was also becoming clear to Mueller and his colleagues was how Atta and his fellow hijackers had at almost every turn unerringly homed in on, and exploited, glaring weaknesses in America's immigration and security apparatus: travelling back and forth into the US from Canada via a tiny border crossing in Jackson, Maine and using the cover of America's closest ally in the Arab world - Saudi Arabia. Mueller's conclusion was that this was an operation that had been planned for years.

STILL there are glaring weaknesses in America's immigration and security apparatus.