WASHINGTON // Saying the United States "cannot capture or kill its way to victory", the US defence secretary has urged the military to do more to prepare for the kind of unconventional battles he believes will define global warfare in the years ahead. In an article to be published in the next issue of Foreign Affairs journal, Robert M Gates - who has served the past two years under George W Bush but been asked to stay on in the Obama administration - says the US should be "modest" in its view of what military force and technology alone can accomplish. And he offers criticism, albeit veiled, of the belief held in the Bush administration in 2003 that the "shock and awe" campaign in Iraq would mean outright, and quick, defeat. "The Taliban were dispatched within three months; Saddam's regime was toppled in three weeks," Mr Gates writes. "But no one should ever neglect the psychological, cultural, political and human dimensions of warfare? We should look askance at idealistic, triumphalist or ethnocentric notions of future conflict? that imagine it is possible to cow, shock or awe an enemy into submission, instead of tracking enemies down hilltop by hilltop, house by house, block by bloody block." The article by Mr Gates is in part a look back at the defence department of the Bush administration. But it also provides a look ahead at how the Pentagon may change under Barack Obama, even with Mr Gates still at the helm. In it, Mr Gates argues that the US must modernise - and maintain the technological edge held by - its conventional military forces. But he says the battles of tomorrow will not necessarily resemble the battles of today or yesterday, or conform to the traditional American view of warfare as direct military conflict. He holds that the states that pose the greatest threats to the United States now are not powerful states but failing ones. Quoting Carl von Clausewitz, the military theorist who wrote the famous treatise On War, Mr Gates says the US must have a military that can, with equal skill and competence, kick down the door and then clean up the mess afterwards. But the use of conventional force may become less common. "The United States is unlikely to repeat another Iraq or Afghanistan - that is, forced regime change followed by nation building under fire - anytime soon," Mr Gates writes. "But that does not mean it may not face similar challenges in a variety of locales." In his view, the US strategy is for an indirect approach: working alongside partner governments and their security forces to "prevent festering problems from turning into crises" that might later demand military intervention. Mr Obama, who takes office on Jan 20, has called Afghanistan the central front in the "war on terror", and about 20,000 additional US troops are headed there as the force size in Iraq is trimmed; the first new brigade will arrive next month. Mr Gates says Afghanistan poses "an even more complex and difficult long-term challenge than Iraq" and will require significant and ongoing military and economic investment from the US. He calls the war on terror itself a "prolonged, worldwide irregular campaign" and a "struggle between the forces of violent extremism and those of moderation". "Direct military force will continue to play a role in the long-term effort against terrorists and other extremists," Mr Gates writes. "But over the long term, the United States cannot kill or capture its way to victory." If the US fails in either Iraq or Afghanistan, it would be a "disastrous blow" to US credibility, he says, as would even just the perception of defeat. eniedowski@thenational.ae