I concur with you on the point that sometimes it is necessary to put ethics aside and cross the moral line in order to ensure security and protect the American populace. Considering the statement that to corner a criminal, one has to think like one, criminals have no rules or laws to abide by. In a case where there is no other option, the intelligence service personnel have to violate some laws when dealing with criminals such as terrorists. As much as this is illegal, I support the claim that sometimes, the undercover agents have to do so since if they do not cross the line, they will not effectively fight terrorism and America may face attacks similar to 911.
Your yardstick of weighing between what is legal, ethical and moral is quite interesting and favorable especially in this topic of handling criminals. The legal aspect is usually ruled out in an instance where the only way out has to be an illegal process. As much as the 2014 National Intelligence strategy demands that the intelligence personnel must stick to some code of ethics that requires respect for human rights, sometimes they have to violate the ethics to save the larger masses.
Torture is usually against the moral nature of human beings. The intelligence personnel however usually employ this method on some suspects in order to derive critical information from them. It is important to note that this method does not work in all cases especially those involving terrorists. Most of them work under oaths and will not let out any secret pertaining their organizations.