Appealing to the global good is harder than it looks
What are the prospects for increasing international cooperation against terrorism?
The only way to increase international commitment against terrorism is to understand international needs regarding terror. Since 9/11, America has felt it is sole owner of the moral yardstick for terrorism -- since 9/11 happened to us, we assume (wrongly) that we feel the devastation of terrorism more than anywhere else. That makes our needs seem more important than any other nation's, including those nations with whom we wish to ally. It also somehow justified our choices of battlefront, including Afghanistan and Iraq. Shortly after the fall of Baghdad, threatening overtures were made towards Syria and Iran as well -- American allies shuddered to discover they may have further battles to fight.
Our stalwart allies, such as England and Australia, will always be there for us. They stand side-by-side with American troops in Afghanistan and Iraq. Other nations, such as Canada and Germany, have joined with us in Afghanistan (but not Iraq) through their NATO obligations rather than having enlisted with us on all fronts which we have chosen.
To bring other nations to our side in global CT efforts, America must explain that all nations are affected and connected by terrorism. This is a global insurgency, between forces of civilization and connectedness and those who would wall off swaths of the world from all development. Those disconnected nations would be united in a worldwide caliphate, the Koran-prophesied establishment of the umma -- the rest of the world would eventually be converted and conquered through constant and unending jihad. This is a state of affairs that cannot be allowed to happen. It is very difficult to sell this line of reasoning to European nations, who have sizable Muslim minorities which can and have affected major rioting and civil unrest, to say nothing of outright domestic terrorism throughout Europe.
I honestly do not know what it will take to get all nations on board for the global fight. Hopefully some appeal to the global good will enlist more to the cause. However, internal demographic unrest may affect foreign policies more than it should.