Why is America Still a Target?

The US will keep its embassies closed around the world because of possible attacks. The state department has also issued a global travel alert. Republican Senator Saxy Chambliss, has said that this is the most serious threat he has seen in the last several years. It is almost 12 years since 9/11, and only two years ago, the US announced the death of Osama bin Laden - with President Obama saying: "Mission accomplished". So why is it that America is still a target?