In the days before President Bush detailed his plan to use the National Guard to beef up border security, the nation wondered whether the commander in chief was again adding to the burdens of an overstretched force.
In the weeks ahead, however, the most pertinent questions might turn toward whether those soldiers deployed on the border will make any significant difference.
The scope of the deployment is so limited - no more than 6,000 soldiers for about a year - that few analysts say it will constrain the Guard's ability to fight the war on terror or respond to domestic emergencies. Yet because of this modest footprint, some wonder whether it can accomplish its goal of sealing America's nearly 2,000-mile border with Mexico.
With the Guard in support, Mr. Bush's plan, set forth in a televised address Monday night, would put 18,000 troops and border patrol agents on the country's southern frontier. Doing the job right, some experts suggest, would require more than twice that number.
"When you realize how manpower-intensive patrolling the border is, you realize this is a stopgap," says Andrew Krepinevich, a defense analyst at the Center for Strategic and Budgetary Assessments in Washington.
Bush essentially acknowledged as much, saying that the National Guard is a temporary fix. The Guard is intended to plug the gap completely for one year. Then, as new patrol agents become available, Guard forces will withdraw, entirely by 2009.
Yet even the ultimate goal - 18,000 border patrol agents - is insufficient, critics say. And in the interim, the National Guard troops will be limited in what they can do. To avoid the perception of a militarized border, Bush has proposed that Guard soldiers refrain from any law-enforcement activities, such as arresting, detaining, or transporting illegal border-crossers.
Instead, they will support the border patrol by providing surveillance, analysis, and engineers for construction projects. "Is that an improvement? Yes. Does it solve the problem? I suspect not," says Christine Wormuth of the Center for Strategic and International Studies in Washington.
The Guard itself is more hopeful. It will bring new technologies like unmanned surveillance aircraft to the border, as well as a history of working with local law-enforcement officials. "The National Guard may be more effective than any other organization out there," says Maj. Gen. Roger Lempke, president of the Adjutants General Association of the United States.
The Guard is perhaps the only tool the president has for this mission on such short notice. It is one of the military's best Swiss Army knives, adaptable to foreign wars, urban riots, rural flood relief, or homeland security.
"When America needs a trained and ready force ... it turns to the Guard," says John Goheen of the National Guard Association of the United States. With some 450,000 members of the Army and Air National Guard nationwide, he adds: "Simple math would suggest this is doable."
It is doable for several reasons, experts say.
First, the Guard's role in Iraq has diminished significantly since last year, when many Army units were not ready to deploy. At one point in 2005, the Guard made up nearly half of US forces in Iraq; today it makes up less than 20 percent. So more members of the Guard are available.
Moreover, though the federal government will pay for the border mission, the four border states - California, Arizona, New Mexico, and Texas - will actually call up the Guard. As a result, state National Guard commanders will decide who to deploy - not the Pentagon. This gives them greater flexibility in using their resources.
Many soldiers will come from the border states. But those states also could call on other states through interstate soldier-sharing agreements called Emergency Management Assistance Compacts.
In some cases, soldiers' tours along the border will only last two weeks - fulfilling their annual requirement for two weeks of training. These will probably be soldiers deployed only to complete a single task - such as building a fence.
Others, however, are expected to deploy to the border for one to three months. National Guard commanders will look to avoid calling up those who have recently returned from Iraq or who could be needed for potential disaster-relief operations.
"This flexibility gives us the ability to reach in a little deeper without compromising the safety of American citizens," says General Lempke.
Numbers in California, for instance, give some idea of the wiggle room. Some 2,200 of the California National Guard's 20,000 troops are deployed on federal missions. Another few thousand are unavailable for various reasons - some because they recently returned from deployment abroad.
That leaves about 15,000. California planners generally like to have 10,000 troops on hand as a hedge against any emergency, leaving the rest available for prudent deployment.
The Pentagon isn't worried about losing capability. "There will be no degradation to National Guard support to the Department of Defense overseas mission," said Lt. Col. Ellen Krenke, a Pentagon spokeswoman,
Some governors and lawmakers remain skeptical. In a statement released Monday, Rep. Ike Skelton (D) of Missouri cautioned: "For years, I have said that our forces are being stretched thin by current operations. This mission along the Mexico border will add unnecessarily to their mission requirements."
Analysts who don't see significant manpower problems raise other questions. "If it's such an urgent security need, why are we just realizing it now?" says Ms. Wormuth. "The immigration debate is a challenging political issue, and the administration is looking for a way to address it - the National Guard is a tool in the toolkit."