The terrorists want a world war between all of Islam and everybody else, because they believe that in such a war Allah will give them the victory and the entire world will become Muslim (or at least be ruled by Muslims).
So leaving them alone will not cause them to leave us alone it will encourage them to provoke us more.
Giving more aid or support to Muslim nations will not be seen as generosity, it will be seen as tribute or ransom money, and the credit will go to the terrorists ... thereby inviting further acts of terror. (This is the pattern that the Palestinian terrorists have already demonstrated for years.)
That is the thing that the advocates of peace just dont seem to understand: Peace cannot be achieved unilaterally. When an enemy is determined to make war even a pathetically weak and under-armed enemy then a war will be fought ... or the enemy will become your conqueror.
War postponed never becomes easier to fight, or less costly in lives and treasure. And those who mock President Bush as a cowboy or even, insanely, claim that America (or the Jews) staged 9-11 just so wed have an excuse for war will not, if their views prevail, bring about peace. They will simply bring about far more death.
And if we abandon this war, then a day will almost certainly come when all of us will look back with deep regret to the time when we might have rid the world of the scourge of extremist Muslim terrorism (meanwhile liberating more than a few Muslim nations from tyranny) at the astonishingly slight cost in blood and horror, compared to most wars, that we have paid so far in Afghanistan and Iraq.
Self-evident, and still not understood by the left.