President Obama's nominee to head the Pentagon's new Cyber Command said the division would primarily focus on its defensive role at his confirmation hearing Thursday morning, downplaying the concerns that it would become a military instrument to wage cyber warfare against hostile nations.

"This command is not about efforts to militarize cyber space," Lt. Gen. Keith Alexander told the Senate Armed Services Committee.

Today's hearing comes nearly six months after Alexander's nomination, delayed in part by lawmakers' concerns about the mandate and role of the Cyber Command, which Defense Secretary Robert Gates announced last June.

But Alexander, currently the director of the National Security Agency, said that much of the Cyber Command's activities would involve supporting and coordinating with other agencies and consolidating the military's information defense systems under a centralized organization.

In theaters of active combat, the Cyber Command would be tasked with supporting the information and communications systems of the U.S. military forces, and could, under the standing rules of engagement, retaliate against the networks of an enemy combatant. He admitted that attribution is always a challenge when dealing with cyber threats, and said that an attack routed through a neutral country would complicate the Cyber Command's response options, but that in a time of war, the division would still have the authority to retaliate against the enemy.

"In general terms, I do think a cyber war could exist, but it would not exist inside itself, but as part of a larger military campaign," Alexander said.

But in times of peace, the role of the Defense Department division in response to an attack on civilian infrastructure is less clear, though it would necessarily involve cooperation with the Department of Homeland Security, the agency responsible for protecting the .gov domain and supporting the private sector in defense of commercial networks.

"That brings in the real complexity of the problem that we face today," he said. "That's probably the most difficult and what we're going to spend the most time working to address."

In addition to the Cyber Command, the administration has taken several steps toward overhauling the federal cybersecurity apparatus, which has long been maligned for outdated laws and policies, interagency turf wars and a climate of secrecy that has cooled relations with the private sector.

Four months ahead of the announcement of the Defense Department's announcement, Obama commissioned a task force to develop a comprehensive review of federal cybersecurity policies and operations. Then in December, he named Howard Schmidt, a former security executive at Microsoft (NASDAQ: MSFT) and at eBay (NASDAQ: EBAY) with a long history of government service, to the position of White House cyber coordinator.

One of the main thrusts of those efforts has been to harmonize the efforts of the military, intelligence and homeland security communities, and their coordination with commercial network operators, utilities and other firms.

"That's the hard issue that I see facing us today," Alexander said. "Most of our infrastructure for our government is owned and operated by the private sector."

In a laudatory introduction at today's hearing, Barbara Mikulski (D-Md.) championed Alexander for the new position, saying that he had taken the NSA in a new direction and created a warmer climate for cooperation with businesses, most recently demonstrated by Google's (NASDAQ: GOOG) work with the agency as it investigates a wave of cyber attacks last year that the company linked to China.

"He needs to be able to deal with the private sector -- they're already coming to him," Mikulski said.

In his five years as the head of NSA, Alexander said that he has deepened the partnership with DHS to provide technical expertise and other assistance to support its cybersecurity work in the civilian sphere.

If confirmed, Alexander said that the Cyber Command would work closely with the NSA to mine its sprawling global intelligence network. With DHS, the Cyber Command's responsibility would be largely supportive, helping the agency prevent cyber attacks on critical civilian infrastructure, such as the electricity grid and gas pipelines.

The position is also aimed at streamlining the Defense Department's internal responses to cyber threats. Alexander reminded the committee that DoD systems are probed hundreds of thousands of times each day by a mix of hostile foreign governments or their surrogates, terrorist organizations and hackers, and that those intrusions have spiked sharply this year.

At the same time, he acknowledged that the new Cyber Command is venturing into "uncharted territory," and said he would be working closely with the undersecretary of defense for policy to clarify the unit's role and legal authority.

John McCain, the ranking Republican on the Armed Services Committee, asked Alexander to submit to the panel a "laundry list" of statutes and policies relating to the Cyber Command that are either unclear or out of date.

Kenneth Corbin is an associate editor at, the news service of, the network for technology professionals.