Admiral Bill McRaven, head of U.S. Special Operations Command, said the lessons of the post 9/11 world are clear.
Local acts of terrorism can quickly become a global phenomenon and it is cheaper to deal early with nations teetering on the brink of anarchy rather than allow them to become regional problems, he said.
The job is not for one nation, McRaven told a packed luncheon at a defence conference.
"The U.S. cannot address the challenges of tomorrow alone. They are too diverse, too unpredictable," he said.
"We don't have the fiscal capability, the manpower, and in some cases the resources to go it alone. None of us do."
To prevent violence-plagued countries from becoming failed states, McRaven said, special forces need to train local forces.
Relationships with security forces in trouble spots are also key.
And countries with highly skilled commando and counter-terrorism units should be more formally bound together on the international level, perhaps under the umbrella of NATO's recently created special forces command.
His pitch stands in contrast to the prevailing wisdom in Ottawa, where the Harper government has made clear it will not send combat troops — commandos or otherwise — to the world's trouble spots, such as Mali.
McRaven says his speech Friday to the Conference of Defence Associations annual meeting was not aimed at Canada, or intended to be political.
"My speech was not an appeal to anyone," he said afterward. "The decisions for Canada are Canada's alone."
While in Ottawa, McRaven held meetings with his special forces counterpart, the country's chief of defence staff and the national security adviser.
The appetite among the governing Conservatives to become entangled in foreign military missions, post-Afghanistan, has all but dried up.
As French forces battled al-Qaida-linked militants in northern Mali this winter, the Canadian government sent only a C-17 transport to ferry war materials with no major commitment, despite the West African nation being among the biggest recipients of Canadian aid and business investment.
The fact the Canadian military is entering a period of retrenchment and cuts was underscored several times Friday by Defence Minister Peter MacKay, who appeared by video conference from a NATO meeting in Brussels, and by Gen. Tom Lawson in his first major speech since being appointed chief of defence staff.
"There's a budget to balance and Defence must do its part," Lawson said.
He described cost-cutting as the military's new "centre of gravity."
There could be up to $2.5 billion carved out of the defence budget by next year, according to an independent analysis last fall.
Admiral Edouard Guillaud, the French chief of defence staff, said many western nations face similar choices.
Guillaud told the conference his country was grateful for the contribution of the C-17 in Mali, and noted there is limited public patience for long military campaigns. About 48 hours after French troops arrived in Mali, he said, the headlines declared the mission had become "bogged down."