New York: President Barack Obama Wednesday said the US will use military force, unilaterally if needed, when its core interests demand it - when Americans are threatened or when the security of its allies is in danger.
International opinion in such circumstances matters but "America should never ask permission to protect our people, our homeland, or our way of life," he said.
"The United States will use military force, unilaterally if necessary, when our core interests demand it – when our people are threatened; when our livelihood is at stake; or when the security of our allies is in danger.
"In these circumstances, we still need to ask tough questions about whether our action is proportional, effective and just. International opinion matters.
"But America should never ask permission to protect our people, our homeland, or our way of life," said the US President at the graduation ceremony of the elite Military Academy in West Point, New York.
It is America that the world looks to for help, for it is the one indispensable nation, he said.
"Here's my bottom line: America must always lead on the world stage. If we don't, no one else will," Obama said.