The method used by the terrorist was simple, but the plan was sophisticated, daring and creative, testifying to a meticulous process.

Mail bombs are nothing new. Israeli intelligence used the method in 1956 to assassinate a colonel in Egyptian intelligence in Gaza, and in the 1960s to attack former Nazis and German scientists working in Egypt.

Later, mail bombs were sent to senior figures in the Palestinian terrorist organizations.

These groups retaliated in kind, delivering similar bombs to Israeli diplomats and emigres.

The choice to use two international carriers - Federal Express and UPS - reflects professional planning and a careful choice of material, timing and targets.

The packages were concealed in printer ink cartridges filled with PETN explosives.

One of the explosive charges was meant to be set off with a timing mechanism, another with a cell phone's SIM card.

The timing of the operation was far from coincidental: The bombs were meant to explode near or on Tuesday, the day of the U.S. midterm elections.

The timing and target - Jewish-American communities - seem to indicate that Al-Qaida did it, and the Yemeni origin of the packages appears to show that the group behind it was the so-called Al-Qaida in the Arabian Peninsula.

Yemenis have been commanders in Al-Qaida ever since Osama bin Laden announced the existence of the organization in a cave in Afghanistan in 1998.

Yemen has also seen a number of terrorist attacks against American targets, including the October 2000 assault on the USS Cole in Aden.

But in recent years, Yemen has become a central operations base for some of the worst attacks.

Radical cleric Anwar al-Awlaki, who preaches from Yemen over the Internet, has been linked by American intelligence to at least six attacks, including the Fort Hood shooting in November 2009 and the attempted Times Square bombing in May 2010.

Three firm conclusions

Three conclusions can be drawn from the attempted attacks of the past week. Radical Islamist terrorism changes shape, but it doesn't disappear. International intelligence cooperation is increasing - the information that undermined these attacks came from Saudi Arabia and was shared with Dubai, the United States and Britain.

Second, it would appear that just as the fundamentalists are setting up terrorism networks, intelligence communities around the globe are establishing counter-networks of agents, informers, handlers and technology.

The third lesson is that although Israel and Jewish targets are not the terror networks' main focus, attacking Jews remains a guiding motivation.