“The existence of the Zionist regime is tantamount to imposition of an unending and unrestrained threat so that none of the nations and Islamic countries of the region and beyond can feel secure from its threat. The closer these nations are to the epicenter of this threat, the more threatened they feel. The people of Palestine are at the very core of such a threat. They have not been able to spend a day with peace of mind for the past sixty years. Three generations of sons and daughters of Palestinians have lived and are presently living under these circumstances. The peoples of Egypt, Jordan, Syria, Lebanon and the entire Middle East are essentially under similar situation.”

Nobel lecture (2005)
Context: A recent United Nations High-Level Panel identified five categories of threats that we face:
1. Poverty, Infectious Disease, and Environmental Degradation;
2. Armed Conflict — both within and among states;
3. Organized Crime;
4. Terrorism; and
5. Weapons of Mass Destruction.
These are all 'threats without borders' — where traditional notions of national security have become obsolete. We cannot respond to these threats by building more walls, developing bigger weapons, or dispatching more troops. Quite to the contrary. By their very nature, these security threats require primarily multinational cooperation.

New York Times Op-Ed "Grounding a Pandemic" (6 June 2005) http://www.nytimes.com/2005/06/06/opinion/06obama.html?ex=1275710400&en=69f51e47097d5dd9&ei=5090&partner=rssuserland&emc=rss by Barack Obama and Richard Lugar
2005

2000s, 2001, Invasion of Afghanistan (October 2001)

S. Harper: ‘Islamicism’ Canada’s Biggest Threat: PM http://www.onislam.net/english/news/americas/453806-islamicism-canadas-biggest-threat-pm.html - OnIslam, September 7, 2011</ref><ref> Harper says 'Islamicism' biggest threat to Canada http://www.cbc.ca/news/canada/story/2011/09/06/harper-911-terrorism-islamic-interview.html - CBC News, September 6, 2011
2011

Paragraph 20
2006, Letter to George W. Bush, 2006

Address to the US Green Party

What I Didn't Find in Africa (2003)
Context: I was convinced before the war that the threat of weapons of mass destruction in the hands of Saddam Hussein required a vigorous and sustained international response to disarm him. Iraq possessed and had used chemical weapons; it had an active biological weapons program and quite possibly a nuclear research program — all of which were in violation of United Nations resolutions. Having encountered Mr. Hussein and his thugs in the run-up to the Persian Gulf war of 1991, I was only too aware of the dangers he posed.
But were these dangers the same ones the administration told us about? We have to find out. America's foreign policy depends on the sanctity of its information. For this reason, questioning the selective use of intelligence to justify the war in Iraq is neither idle sniping nor "revisionist history," as Mr. Bush has suggested. The act of war is the last option of a democracy, taken when there is a grave threat to our national security. More than 200 American soldiers have lost their lives in Iraq already. We have a duty to ensure that their sacrifice came for the right reasons.

Speech to the Michigan legislature, in Lansing, Michigan (15 May 1952), published in General MacArthur Speeches and Reports 1908-1964 (2000) by Edward T. Imparato, p. 206; part of this was also used in a speech in Boston, as quoted in TIME magazine (6 August 1951) http://www.time.com/time/magazine/article/0,9171,856843,00.html
Context: Talk of imminent threat to our national security through the application of external force is pure nonsense. Our threat is from the insidious forces working from within which have already so drastically altered the character of our free institutions — those institutions we proudly called the American way of life.

As quoted in "America's Next Top Fearmonger: The presidential candidates compete to scare the daylights out of the U.S. public." http://nationalinterest.org/feature/america%E2%80%99s-next-top-fearmonger-12954 (22 May 2015), by Robert Golan-Vilella, National Interest
2010s