As the man responsible for the health and strength of the U.S. military, Pentagon chief Robert Gates is increasingly finding himself between the devil and the deep blue sea.

On the one hand, there’s the devil in his Iraq-obsessed boss, President George W. Bush, who clearly opposes any move that could risk what gains have been made in curbing sectarian violence and establishing a semblance of stability over the past six months.

So when Bush’s commander on the ground, Gen. David Petraeus, insists that reducing U.S. troop strength in Iraq below 130,000 could jeopardize whatever chances remain of snatching "victory" from defeat there, Gates, who had previously favored reducing U.S. troops in Iraq to as few as 100,000 by the end of this year, is forced to defer. He did just that Monday when, after meeting Petraeus in Baghdad, he announced for the first time that he supported a "pause" in the ongoing drawdown when pre-surge levels are reached in July.

On the other hand, there’s the deep blue sea in the rapidly growing conviction among top military officers and the national security establishment in general that U.S. ground forces are already dangerously overstretched and that retaining 130,000 troops in Iraq is simply not sustainable.

Indeed, those top military officers, notably Chairman of the Joint Chiefs of Staff Adm. Michael Mullen and Army Chief Gen. George Casey, have become increasingly vocal in recent weeks about their concern that Iraq is systematically transforming the U.S. military into what one expert, former Navy commander Harlan Ullman, called "a ‘hollow force’ reminiscent of the post-Vietnam War."

"If this is happening … should we be faced with the choice of staying in Iraq with 130,000 or so troops or eviscerating our military?" asked Ullman, who developed the "shock and awe" strategy during his tenure as professor of strategy at the National War College, in his weekly column in the Washington Times last week. "Do we put the future of Iraq ahead of the future of our armed forces?"

That point is being made with growing intensity by the Pentagon brass, albeit it somewhat more diplomatically. "Our service members, in particular our ground forces and their families, are under significant strain," Mullen said last week, stressing that current 15-month deployments of U.S. soldiers and marines are "too long" and must be reduced to 12 months as a matter of urgency. "The well is deep, but it is not infinite," he warned.

Even his normally reticent predecessor, former Joint Chiefs Chairman and Secretary of State Colin Powell, who worked closely with Gates during the George H.W. Bush administration, felt compelled to weigh in. In a television interview, he warned that even pre-surge troop levels "can’t be kept up indefinitely."

But it is not only the effect on the morale and capabilities of U.S. ground forces that the experts are concerned about. Mullen, Ullman, and others point to yet another deep blue sea—the growing dangers posed by the Taliban insurgencies in both Afghanistan and nuclear-armed Pakistan—to make the point that Washington may be facing threats greater that those it faces in Iraq.

"We must not allow the challenges of today to keep us from being prepared for the realities of tomorrow," Mullen said last week. "There is a risk that we will be unable to rapidly respond to future threats to our vital national interests," he added in what appears to be the consensus among the national security elite and one in which Gates no doubt shares.

Indeed, the growing consensus among the national security professionals embraces the notion that Afghanistan and Pakistan, particularly the Pashtun areas along their common border, have become the "central front" in Bush’s "global war on terror," even if the president himself still believes that that war will be won or lost in Iraq.

The U.S. intelligence community—Gates’ home during most of his professional career—has long thought that Iraq was a diversion from the antiterrorist campaign, a point it underlined in a National Intelligence Estimate (NIE) published last July.

The NIE concluded that al Qaeda has largely rebounded from its eviction from Afghanistan six years ago and reconstituted both its central organization and some of its training and operational capacities in the safe haven established by the Pakistani Taliban in the Federally Administered Tribal Areas (FATA) along the Afghanistan-Pakistan border.

In remarkable testimony before Congress last week, Director of National Intelligence Adm. Mike McConnell went even further, stressing that al Qaeda has "regenerated its core operational capabilities needed to conduct attacks" on the United States itself. In written testimony, Mullen, Gates’ chief military advisor, reiterated that point, noting that he believed the next terrorist attack on the United States would probably originate with al Qaeda operating out of FATA.

Mullen was on his way at the time to Pakistan for meetings with President Pervez Musharraf and Army chief Gen. Ashfaq Parvez Kayani, reportedly to impress on them Washington’s worries about the spread of the Taliban insurgency and to reiterate recent U.S. offers not only to sharply increase intelligence military aid, training, and advisors to Pakistani forces, but to engage in "joint operations" on the Pakistani side of the border.

His visit was the latest in a string of top-level U.S. delegations—indicative of how central the national security bureaucracy sees Southwest Asia—dispatched by Gates and the intelligence community to Islamabad in just the past month.

Delegations have included McConnell; head of the Central Intelligence Agency Gen. Michael Hayden; Commander of U.S. Special Operations Command Adm. Eric Olsen; and Chief of the U.S. Central Command (CentCom) Adm. William "Fox" Fallon, who has reportedly clashed repeatedly with Petraeus over the relative importance of Iraq vis-à-vis the larger regional situation, particularly in Southwest Asia.

Despite his tentative siding with Petraeus on the question of "pausing" before considering further withdrawals from Iraq after July, Gates himself suggested on the way to a meeting with other NATO defense ministers in Munich that Bush’s obsession with Iraq carried serious diplomatic and military costs both for the fight against the Taliban and al Qaeda and for the future of the NATO alliance.

"I worry that for many Europeans the missions in Iraq and Afghanistan are confused," he told reporters, explaining why Washington’s NATO allies were reluctant to send more troops to Afghanistan despite Gates’ increasingly urgent appeals. "Many of them, I think, have a problem with our involvement in Iraq and project that to Afghanistan, and do not understand the very different … kind of threat."

Jim Lobe is the Washington bureau chief for the Inter Press Service and a contributor to PRA’s Right Web (https://rightweb.irc-online.org). He blogs at http://www.ips.org/blog/jimlobe.