Previous wars with the Imperium quickly showed the inadequacy of frontal attacks on imperial forces, since the enemy's legions had a very clear edge in firepower and protection. A frontal assault on imperial forces often meant using enormous numbers of infantry and armour, and would also often lead to high losses and exhaustion. Even if a breakthrough was achieved, the offensive would often be slowed down or even halted by battle exhaustion.
Thus the Federation's generals abandoned the idea of the frontal attack. With the advent of the grav tank and SUPRA's specialist units, new strategies were elaborated, most notably "deep battle". The main idea of deep battle operations was to conduct simultaneous "shock" attacks on weak points in the enemy frontline. These attacks would be carried out by SUPRA and specially selected "shock armies" that would, with the help of artillery and air support, smash through these points. Once a breakthrough or several breakthroughs were achieved, large masses of mechanised infantry and armoured units would then pour through them and advance deep into the enemy's operational rear. Such attacks would usually be supported by airborne/spaceborne units operating in the enemy's rear, disrupting communications and taking away his ability to focus his forces and reinforcements until the breakthrough had been achieved.
Once a breakthrough had been achieved, Federal forces would use their superior speed and mobility to make any defensive or counter-offensive strategies impossible. This doctrine proved remarkably effective in the Taloria conflict, with the Imperial-Fusilian line of defence practically collapsing in the face of the Federal offensive. One captured Fusilian volunteer said the following about the Federation's attack:
"When the line was pierced, we were ordered to fall back to a line of hills...but when we got there, the Reds were there already. So we were ordered to retreat to a large river...but the Reds had already reached it. Holding a position became impossible. They were just everywhere, and all we did from the central mountain range to Dussala was retreat."
The last time Deep Battle was put into effect was in the brief Commonwealth-Federation Border War, during which the first waves of the Sonran counter-offensive were all but wiped out after being flanked by Federal armoured units. Only the deployment of experimental weaponry (such as the microwave tank) enabled the Sonrans to gain the upper hand, and even then victory was only achieved with high losses.
