In studying Israeli public opinion in the face of an attack from an external enemy the author points out that the emotions evoked among the public may differ depending on whether the enemy is a non-state armed group such as Hamas or Hezbollah or a modern state with an army and weapons of mass destruction such as Iran. This study argues that the rally-round-the-flag (RRTF) may be triggered by anger when the enemy is Hamas or Hezbollah and by feelings of fear and anxiety when the enemy is the Iranian national army. The author also found that the RRTF does not occur when the scale of the attack from the enemy is much larger than the conventional level. Thus, the study examines the conditions that cause the RRTF effect and uses a survey experiment to clarify the underlying political psychological mechanism. The experiment includes a scenario of a direct attack by Iran which was only imaginary in 2020 when the experiment was conducted. In 2024, when an Iranian attack on Israel is a reality, the results of this study can be considered prophetic.