A society always needs enemies. Or rather a political cause does. A society that pursues peace with a former enemy, usually does so at the cost of finding new enemies, usually enemies at home.
The left which believes itself above this kind of politics, in fact vigorously practices it. When the progressive camp preached against Red-Baiting, it was not because they sought a different kind of politics than one premised on demonizing your opponents and conducting smear campaigns against them-- but because they felt there were worthier enemies at home to demonize and conduct smear campaigns against.
With the Cold War over and the Democrats in power, the Clinton Administration did its best to convince us that the real threat to America came from the Militia Movement-- and possibly right wing talk radio.
In Israel this was paralleled by the "Peace Process" in which Israel set up a Palestinian terrorist entity within its borders and declared that a New Middle East was here-- and the Labor Party promptly turned on its old enemies, the Likud and the right and declared that they were the real threat to the nation.
After the assassination of Prime Minister Rabin, which occurred under extremely dubious circumstances, the ruling Labor Party set to work blaming every conservative in Israel for the murder, Likud Party offices were trashed and people were called in on suspicion of making jokes about Rabin.
This pattern resumed again under Sharon, who once having decided that he wanted to create a Palestinian state and forge a center coalition, conducted a vicious and ruthless campaign against the Settlers-- created a new enemy to fight in place of the one he had given up trying to defeat. The tactics involved the physical expulsion of thousands and the destruction of their homes followed by an organized and active effort to maintain them in a dispossessed state by destroying their economic prospects, expelling them from temporary locations by pressuring more than one Kibbutz to withdraw its offer and even leveraging a tax on donations of used clothing from abroad.
The Israeli left which styles itself as enlightened peace activists had worked hard and continue to work hard to make war on a section of Israeli society with hateful rhetoric, with provocations and with prisons and beatings. While Arab terrorists are freed to kill again, teenage girls have been imprisoned simply for participating in opposition rallies. Society needs an enemy.
In the United States, the most vocal voices of the Anti-War movement call for "Peace" but like their Israeli counterparts, they do not mean a universal peace, but rather peace with the terrorists and war against their domestic political enemies. The Republican right, they argue, are a bigger threat than Al-Queda. The slogan could be summed up as "Hands Off Osama and Impeach Cheney."
If the wars of conservatives against foreign enemies also provide opportunities for politically hammering progressives, progressives prefer to dispose of the wars and let the enemy win and focus their attention purely on their domestic enemies. Given a choice between a Republican victory and a Communist or Al-Queda victory-- Liberal Democrats have repeatedly demonstrated a preference for the latter. A society needs enemies and if conservatives find them abroad in defending their country against outside threats, progressives see any ideology but their own as the gravest threat.
In Israel that has led to a country tearing itself apart, fighting itself while the enemy only gains in strength. In America that has led to a political opposition that does everything possible to help the enemy win, so long as it wins them the election.