When is propaganda most used?

Propaganda is most used during wartimes because politicians usually need to shape perceptions of people to get their endorsement of a critical issue like wars as well as they need to defeat their enemy using different tactics, one of which is the psychological war.

The current unjustifiable Israeli war on Gaza is a recent example of how propaganda can support arms and weapons. Regardless of the fact that the Israelis seem not to be successful in their campaign to persuade the world about the legitimacy of launching the war, which is obvious in the demonstrations taking place in most countries, they managed at least to convince many people that they need to defend themselves. To do so, the Israelis tended to use some propaganda techniques such as:

Pinpointing the Enemy http://library.thinkquest.org/C0111500/proptech.htm

Israel used this technique to show that they are fighting terrorism represented by Hamas. They managed to simplify a complex situation by presenting one specific group as the enemy. However, the situation is more complex than that because Hamas is not a group of individuals coming from the middle of nowhere. Whether we agree with it or not, Hamas is a legitimate authority elected democratically by the Palestinian people in 2006 during an election process supported by many countries one of which was the United States.
Although presented as a fight between Israel and Hamas, it is very difficult to convince the International Community, when Palestinian civilians are being killed every day that the current Israeli war aims at fighting terrorism.

Glittering generalities http://en.wikipedia.org/wiki/Institute_for_Propaganda_Analysis

This technique has been practiced by Israel when using emotionally appealing words associated with highly-valued concepts and beliefs without presenting supporting information or reason. Israel is using this technique to stimulate emotions of the world such as love of living in peace and security, and desire for self-defense and protection. These concepts usually get approval without examination of the reason.

Card stacking http://en.wikipedia.org/wiki/Institute_for_Propaganda_Analysis

Card stacking, or selective omission, is one of the seven techniques of Propaganda identified by the Institute for Propaganda Analysis. It involves only presenting information that is positive to an idea and omitting information contrary to it.
In this context, it is true what Israel is mentioning about the fact that Hamas is firing rockets to Israel. However, what has been deliberately ignored is that Hamas is doing so because Israel has been putting Gaza under a complete siege for the last few months. People in Gaza could not anymore access food, water, medicines and get electricity. Moreover, the fact that Israel did not allow journalists and reporters to enter Gaza and cover or broadcast news http://www.nytimes.com/2009/01/07/world/middleeast/07media.html?hp  is an indicator that the information about the war is exclusively originating from one source which is Israel.

Stereotyping http://library.thinkquest.org/C0111500/proptech.htm

This technique is often useful in convincing uninformed audiences. The fact that some terrorist attacks around the world were caused by Islamic extremists, made any Islamic movements look aggressive and terrorist. The case of Hamas resisting Israel is completely different because 1.Israel occupies the territories in violation of international law, 2. Israel has never recognized the right of Palestinians to any part of their homeland 3. Israel’s violence, including attacks on civilians has been out of all proportion to that of the Palestinians. http://www.dissidentvoice.org/2008/05/zionist-ideology-and-propaganda-in-israel-america-and-germany/

Lesser of Two Evils http://library.thinkquest.org/C0111500/proptech.htm

Israel has used this technique to justify difficult decisions. This technique is often accompanied by putting blame on an enemy country. Although Israelis have had other peaceful options than launching a war, they presented this option as the most effective one available on the table and accordingly managed to persuade the majority of their people about the necessity of taking this action.

In conclusion, during wartimes, propaganda seems to find a flourishing environment where the mass, especially the less informed people, tend to become less rational, more emotional and ready to believe news coming from different directions.