Some of these are well-known: sequestration, dim prospects for future military budget growth, and defense technology research and development, which for practical purposes has come nearly to a dead-stop.
Perhaps most serious, however, is how top military and civilian leaders can define the Army's role as the nation moves into the future, how they identify the top threats the Army must face, and how they justify the need for a large standing Army in an era when large-scale big-iron military land battles appear to be part of the past.
Here's where we are today: U.S. military forces are finishing their exit from Iraq, where they have operated for more than a decade. Their final exit from Afghanistan is but a few years off, or less. When operations in Southwest Asia are completed, where does the Army go from there?
Think about it. The Army has had a clear set of missions since the U.S. entered World War II. Although the close of that war saw a rapid drawdown in U.S. military power, the strengthening Soviet Union at that time weighed heavily on everyone's mind.
Less than five years after World War II ended, North Korean invaded South Korea, which created another sudden and dire mission for the Army. That mission grew from containing North Korean forces to containing Communism around the world, which continued until the fall of the Berlin Wall in 1990.
One year later, Iraq invaded Kuwait, which triggered Operation Desert Shield, and eventually the military ouster of Iraqi forces from Kuwait in Operation Desert Storm. In both these military initiatives the Army played a central role.
For the next decade keeping an eye on a contained-but-restless Iraqi military, on ethnic strife in what then was Yugoslavia, and on other simmering hot spots throughout the world held the Army's attention and helped shape its mission.
Today, however, we find ourselves in different circumstances. Counter-insurgency operations are nearing an end in Iraq and Afghanistan, Russia does not pose the immediate military threat that did its predecessors of the Soviet Union, and Europe has been relatively quiet.
Still, trouble spots persist in areas like Syria and Iran, yet with no open conflict involving U.S. Army forces. There is no immediate and dire threat in these areas, and hence no clear Army mission -- at least not yet.
So how does the Army move forward? Counter-insurgency? Certainly. Special Forces capability? Of course. But what's the role of the established Army infrastructure that involves large combat infantry units, main battle tanks, armored fighting vehicles, and an order of battle designed for large ground conflicts?
I'm not sure there is a role, and I'm not convinced that the top Army leadership today knows what its role in the future will be, either.
Maybe the Army simply is at a moment of transition, and leaders will get a handle on the Army's core mission sometime soon. On the other hand, with the civilian leadership vacuum we have today in Washington, I'm not sure the Army will be able to do so.
This leaves the defense industry charged with supporting the Army perhaps in a more precarious position than it has been since the end of World War II nearly 70 years ago. If Army leaders are unable to define the Army's long-term mission clearly, then the defense industry will have no idea how to proceed, other than to guess.
These factors were on display just below the surface last week at the Army's big annual trade show in Washington -- the Association of the U.S. Army (AUSA).
Show exhibits revolved around what has been important up to now -- IED-proof wheeled armored vehicles, fast-response air power in the form of tiltrotor aircraft and fast helicopters, advanced body armor, and network-centric warfare equipment like wearable computers, small software-defined radios, and agile satellite communications.
What was striking at AUSA, however, was a lack of direction in where we go from here. It was as though the industry were pointing out to the Army officers walking the aisles how far technology has led us to this moment, yet pleading for direction on where the industry should go from here.