Israel has always had a very powerful military to back it up. In addition, they have some great and powerful allies, such as the United States. It has also been a nation with a tight set of morals and beliefs. This is different from the many opposing views from neighboring countries.
The previous post was quite accurate. The consolidation of power in Israel, as well as its fervent support of the military and intelligence operatives in conjunction with the backing of the United States has helped and continues to help Israel not merely survive in the region but assume a strong role of power in it. I might also add that the Arab states which border Israel have also faced some internal dissension in their own power bases and have not been able to embrace one another in pure alliances against Israel. The lack of unity both internally and amongst themselves and the relative cohesion in Israel might start to explain the current state of geopolitical affairs in the region.
Great answers thus far. To add to them, keep in mind that Israeli society is motivated by the fact that they are always a target for destruction. With their backs to the Mediterranean Sea, there is either a successful defense of their country or there is their genocide, with very little room for error in between.
Certainly, as previously stated, having the US as an ally, with the $3 billion in foreign (mostly military aid) provided from the United States each year helps Israel to maintain one of the world's toughest and most well trained armed forces. On top of this, it is widely believed that Israel has upwards of 50 nuclear weapons, a fact not lost on Arab states that might wish to attack it.
The US and Israel are home to over 95% of the world's Jews, so if Israel were ever to get in serious defensive trouble, you can bet the US would respond militarily to protect them. So far, they've been able to defend themselves just fine. Arab armies have mostly been less well armed and trained over the years.
Pohnpei's previous answer is right on the money. Israel's military (and particularly its air force), boosted by the purchases of top-flight equipment from its ally, the United States, is one of the strongest in the world. Military service is mandatory for both men and women, and all men are automatically enlisted into the reserves upon completion of their compulsory tenure. The nation's intelligence service is also far stronger than their Arab neighbors, and Israel also maintains reconnaisance satellites for further monitoring of its enemies. Israel's overwhelming victory over the combined forces of Egypt, Jordan and Syria in the Six Day War of 1967 added further territory to its boundaries. Israel also survived a surprise attack by Egypt and Syria during the Yom Kippur War of 1973, again defeating their Arab neighbors. As a Jewish state surrounded by hostile neighbors, Israel realizes its plight and has taken the initiative to defend itself--and to go on the offensive when necessary--at all costs.
The most usual explanation for this is that Israel has been able to A) have a very strong military and B) have a strong ally in the United States.
The Israeli military has always been stronger than the militaries of any of the Arab countries that surround Israel. This is largely because Israel is a more modern state with a more modern form of government. This allows Israel to have much better organization and training in its army than the Arabs do. The Israelis are also able to buy top-class weaponry from the United States.
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