A Modern Fortress
To create the toughest modern fortress I would rely on the following requirements:
1 – Location is critical.
Earlier on this thread we discussed Patton’s attack on the fortress at Metz which is a classic example. Patton had no alternatives to taking the fortress unless he was willing to just wait out the rest of the war in front of it. It should also be noted that the fortifications were built before WWI, had not been maintained, were stripped of the majority of its weapons in the years before the battle, and were manned by troops not trained in its use. It still took 3 months to knock out enough of it to allow passage.
The fortress must be located such that the enemy absolutely must take the ground quickly or not at all, and reasonably intact. Starving the defenders out or resorting to nuclear weapons cannot be permitted as viable tactics by the attacker. The only reliable reason for this would be that it is the only practical route for logistics, i.e. a choke point. One advantage of these locations is that there are already a road/track/harbor for your own logistics, and almost always a city is present as these would have been prime locations for trade (and taxing trade).
2 – Defensives
There are 4 parts to the defenses – ground defenses, artillery, air defenses, and air support – that each contribute and must be overcome by the attacker. Coverage of each system extends beyond the previous system, so that at the point where a ground attacker actually reaches the ground defenses all 4 parts are at maximum effectiveness. Ground attackers have to overcome these in the order listed, penetrating the ground defenses to overrun the artillery, air defense batteries, and airfields. Attacks from the air deal with the defenses in the opposite order, establishing air superiority so that they can take out the air defenses, then destroy the artillery and ground defenses.
3 – The fortifications
Ideally most killing will be by the artillery, but for less valuable targets other options will be required.
C3I
The greatest strength of a carefully prepared modern fortification will be it the web of sensors deployed in front of it. Extensive preparation allows better concealment, the use of physical communication links (probably fiber optic) so there are no signals to detect and a much wider bandwidth that can be exploited for detailed analysis from multiple sensors, and calibration to optimize performance and eliminate holes. The greater bandwidth also would allow the use of sensors not practical in mobile operations. Current remote sensors, because of restrictions imposed by using radio signals, send little more information than “there is activity near me”, whereas for a fortress with hardwired sensors the result may be as detailed as ‘there is an 11 man squad proceeding on trail TR32, coordinates xxxx.yyyy, speed 2 miles per hour, and one of them is complaining about the quality of the toilet paper’.
The enemy should be able to take it as a given that any unit within range of the defensive artillery can be targeted at will. Therefore finding and destroying these sensors will be the enemy’s primary objective throughout the siege. In the case of deeply buried seismic sensors this may be extremely difficult. Likewise, one of the defenders main tasks will be to prevent the attacker establishing his own coverage, most likely using robotic vehicles.
The sensor web should if possible also extend miles beyond the defensive perimeter allowing the defender to monitor the build-up leading to an attack and plan their response.
Concealment
Smart weapons can destroy any target that can be pinpointed. The best defense is to prevent that from happening until the attacker is already in the danger zone of his own weapons, then make it difficult for him to retreat without casualties.
When practical tunnels should be constructed to move troops and maintenance personnel as needed, and to be able to deploy new weapons and sensors in depleted areas, if not actively by enemy troops.
The command and control centers need to be redundant, in multiple locations, and deep underground, as these are critical to the operation.
Disposable
Once a weapon fires it must be assumed that its location can be determined by units in line-of-sight, and it will be targeted and destroyed. Manned bunkers are therefore of very limited value in open terrain, and remote weapons, mostly one-shot, should be deployed instead. Weapons of choice will probably be minefields, claymore mines, and self-forging fragment mines for anti-armor work. Metalstorm also has some concepts that would be good for salvoes of grenades or mines against infantry. It may be possible to get multiple uses from carefully concealed and silenced robotic snipers.
This also affects the choice of artillery. Static artillery is just a target. Mobile artillery can displace to avoid counter batter fire, but is likely run out of possible positions in short order. The slow rate of fire for tube artillery limits their effectiveness between displacements, therefore MRLs with individually programmable rounds will probably be best – setup, then ripple the load at the maximum rate of fire with each round allocated to a different target. Best would be disposable MRLs, so that even a fast and extensive counter-battery fire would be worthless. NETFIRES would have also been a good choice in this role.
Air defense should be limited to CAP and SAMs. As with the artillery, SAMs should use mobile or disposable launchers, located close to the front to maximize coverage, if practical targeting data will be supplied by passive sensors. The aircraft component should be almost exclusively fighter aircraft and UAVs in a defensive role. It should include UAV fighters optimized to hunt down and kill enemy recon UAVs.
Depth & dispersion
Concentrated defenses are too vulnerable, they must be dispersed, which means the depth of the defenses needs be increased. You will not fight for every inch, but you will make the enemy bleed. Concealment and tactics play a role here as well, it may be desirable to allow an enemy to penetrate partway through the defenses, then use weapons behind him to cut him off and counter attack.
The city will be the final line of resistance. The same methods can be deployed as in the outer defenses, but unless included in the buildings during construction will be much harder to conceal. Here reinforced firing positions are infantry are still of value, but troops will need to relocate frequently.
Tunnels are extremely important in cities to provide access ways and safe locations to rest. Carefully concealed, deliberate, tunnels that permit troops to appear unexpectedly in an opponent’s rear areas can be of particular value both for the physical and psychological effects.
4 – Troops
Mechanized troops will be needed for performing limited counter-attacks, or at least threatening to do so, to force the attacker to extend his perimeter and increase the required troop strength. With most of the defenses until active control the defending forces can attack at almost any point, then retreat covered by an automated ambush if the attacking forces attempt to pursue. Infantry forces can be used to infiltrate enemy lines, especially if a covered route (tunnel) is available to pass through their lines, and in the defense of the city.
=======================
Some final notes:
No fortress is so strong that it cannot be overcome, but it will take time (or treachery) to do it. The whole point is to tie-up as many enemy troops as possible for as long as possible with the minimum of your own forces, leaving the rest of your forces (hopefully a superior force to the rest of the enemy forces) free to defeat the enemy elsewhere. Or as some experts have noted: “The purpose of a fortified position is to hold an enemy by the nose while a superior force maneuvers to break his legs.”
Relative cost – Sure you can take out a machine gun nest with a $20,000 smart bomb, but is that cost effective? And the cost includes not only the cost of the bomb, but the aircraft, fuel, etc., and the fact that you will not have that bomb available later for some other possible target, and if there are air defenses, either CAP of SAMs, there is also the chance you may lose the aircraft as well. So is it worth it, or do you just send in the PBI? This is what makes a properly designed and supported fortress so expensive to take. Figuring out the correct answer is what makes someone a good commander, and gives him ulcers. :lam
