The longer and complete form of the first question in the headline is – When is a terrorist not a terrorist in the eyes of the Obama administration (not to mention all of its predecessors) and the governments of the Western world?
Answer: When he or she is an Israeli Mossad agent or asset.
In the case of the assassination of Iranian scientists, the Mossad’s assets are almost certainly members of the Mujahedin-e Khalq Organization (MKO) also known as The Peoples’ Mujahedin of Iran, which is committed to overthrowing the regime of the ruling mullahs. Many of its activists are based in Iraqi Kurdistan where Mossad has a substantial presence. It does the training there, selects the targets in Iran and provides the bombs and other weapons, and MKO members do the actual killing.
It’s reasonable to presume that Mossad is more comfortable operating out of Iraqi Kurdistan with Iranian MKO assets than it was when its own agents were posing as CIA officers to recruit members of Jundallah, a Pakistan-based Sunni extremist organization, to carry out assassinations and attacks on installations and facilities in Iran.
Some of the essence of that Israeli false flag operation has been revealed by Mark Perry in an article for Foreign Policy. His report is based on information he acquired about memos buried deep in the archives of America’s intelligence services which were written in the last years of President George “Dubya” Bush’s administration, plus conversations he had with two currently serving U.S. intelligence officials and four retired intelligence officers who worked for the CIA or monitored Israeli intelligence operations from senior positions inside the U.S. government.