Pentagon Tries to Counter Low-Cost but Potent Weapons WASHINGTON - President Obama's new military strategy has focused fresh attention on an increasingly important threat: the use of inexpensive weapons like mines and cyberattacks that aim not to defeat the American military in battle but to keep it at a distance. The president and his national security team predict that the security challenges of the coming decade will be defined by this threat, just as the last one was defined by terrorism and insurgency. A growing number of nations whose forces are overmatched by the United States are fielding these weapons, which can slow, disrupt and perhaps even halt an American offensive. Modern war plans can become mired in a bog of air defenses, mines, missiles, electronic jamming and computer-network attacks meant to degrade American advantages in technology and hardware. It is a lesson that potential enemies drew from the way American public support for the wars in Iraq and Afghanistan plummeted as armored vehicles - each costing millions of dollars - were broken and their troops killed and maimed by roadside bombs costing only a few hundred dollars apiece. China and Iran were identified as the countries that were leading the pursuit of "asymmetric means" to counter American military force, according to the new strategy document, which cautioned that these relatively inexpensive measures were spreading to terrorist and guerrilla cells. At his announcement at the Pentagon last week, Mr. Obama said the country should invest in "the ability to operate in environments where adversaries try to deny us access." The new strategy specifically orders that efforts to counter the threat, which the military calls "anti-access, area-denial," become one of the 10 primary missions of the American military. That will help define how the four armed services compete for shares of a shrinking Pentagon budget. "The United States must maintain its ability to project power in areas in which our access and freedom to operate are challenged," the strategy document said. Sophisticated adversaries will use asymmetric capabilities, to include electronic and cyberwarfare, ballistic and cruise missiles, advanced air defenses, mining and other methods to complicate our operational calculus. For example, in recent exercises by the naval arm of the Revolutionary Guards, Iran has practiced "swarming" attacks by a number of small, fast boats that could be loaded with high explosives; if one such boat got through, it might blast a hole in the hull of a major American warship. "Iran's navy - especially the naval arm of Iran's Revolutionary Guards - has invested in vessels and armaments that are well suited to asymmetric warfare, rather than the sort of ship-to-ship conflict that Iran would surely lose," Michael Singh, managing director of the Washington Institute for Near East Policy, wrote in a recent essay for Foreign Policy. With Chinese and Russian help, Mr. Singh added, Iran is also fielding sophisticated mines, midget submarines and mobile antiship cruise missiles. Nathan Freier, a senior fellow at the Center for Strategic and International Studies, said, "Iran's capabilities are best suited for imposing high costs on those who might need to force their way through the Strait of Hormuz, and on those in the region whom the Iranians perceive as being complicit in enabling foreign access." The potential challenge from China is even more significant, according to analysts. China has a fleet of diesel-electric attack submarines, which can operate quietly and effectively in waters near China's shore to threaten foreign warships. China also fields short-, medium- and long-range missiles that could put warships at risk, and has layers of radar and surface-to-air missiles along its coast. Finding, identifying and striking an American warship is a complex military operation. But the thicket of Chinese defenses could oblige an American aircraft carrier and its strike group to operate hundreds of miles farther out to sea, decreasing the number of attack sorties its aircraft could mount in a day and diminishing their effectiveness. Perhaps most worrisome is China's focus on electronic warfare and computer-network attacks, which might blunt the accuracy of advanced American munitions guided by satellite. To counter these threats, the Air Force and Navy set up an office to develop complementary tactics and weaponry for what they are calling air-sea battle. One idea is to attack an outer ring of enemy air defenses with F-35 Joint Strike Fighters, opening an alley for an F-22 stealth jet carrying sensitive surveillance pods to fly deeper into contested territory, where it could, for example, guide a powerful sea-launched cruise missile to a mobile or hidden target. According to Lt. Gen. Herbert J. Carlisle, the Air Force deputy chief of staff for operations, plans and requirements, American computer warfare techniques could be used to spoil an adversary's decision-making process. "If we can give them bad information, or we can make them doubt the good information they have," he said. Vice Adm. Bruce W. Clingan, the Navy's deputy chief for operations, plans and strategy, said the military was carefully studying anti-access, area-denial techniques to pinpoint potential weaknesses in an adversary's ability to identify and strike American targets. Do you take out his ability to shoot? Do you take him out once he's shot? Do you deny him accuracy once the missile is airborne and then you create a greater "miss distance"?" Admiral Clingan said. You have to work your way across that entire effect chain and how you're going to do those things to keep those missiles from threatening you. Gen. Martin E. Dempsey, the chairman of the Joint Chiefs of Staff, will soon release his concept for operating in an anti-access, area-denial environment. The 65-page directive will identify 30 capabilities that the armed forces will need to carry out missions across contested battlefields.