"I was reading Vauban."

"You think we don't know how fast you read?"

"And thinking about Vauban?"

"All right then, what were you thinking?"

"Like you said. About how it applies to war in space." Buy some time here. What does Vauban have to do with war in space?

"I'm waiting," said Dimak. "Give me the insights that occupied you for two hours just yesterday."

"Well of course fortifications are impossible in space," said Bean. "In the traditional sense, that is. But there are things you can do. Like his mini-fortresses, where you leave a sallying force outside the main fortification. You can station squads of ships to intercept raiders. And there are barriers you can put up. Mines. Fields of flotsam to cause collisions with fast-moving ships, holing them. That sort of thing."

Dimak nodded, but said nothing.

Bean was beginning to warm to the discussion. "The real problem is that unlike Vauban, we have only one strong point worth defending – Earth. And the enemy is not limited to a primary direction of approach. He could come from anywhere. From anywhere all at once. So we run into the classic problem of defense, cubed. The farther out you deploy your defenses, the more of them you have to have, and if your resources are limited, you soon have more fortifications than you can man. What good are bases on moons Jupiter or Saturn or Neptune, when the enemy doesn't even have to come in on the plane of the ecliptic? He can bypass all our fortifications. The way Nimitz and MacArthur used two-dimensional island-hopping against the defense in depth of the Japanese in World War II. Only our enemy can work in three dimensions. Therefore we cannot possibly maintain defense in depth. Our only defense is early detection and a single massed force."

Dimak nodded slowly. His face showed no expression. "Go on."

Go on? That wasn't enough to explain two hours of reading? "Well, so I thought that even that was a recipe for disaster, because the enemy is free to divide his forces. So even if we intercept and defeat ninety-nine of a hundred attacking squadrons, he only has to get one squadron through to cause terrible devastation on Earth. We saw how much territory a single ship could scour when they first showed up and started burning over China. Get ten ships to Earth for a single day – and if they spread us out enough, they'd have a lot more than a day! – and they could wipe out most of our main population centers. All our eggs are in that one basket."

"And all this you got from Vauban," said Dimak.

Finally. That was apparently enough to satisfy him. "From thinking about Vauban, and how much harder our defensive problem is."

"So," said Dimak, "what's your solution?"

Solution? What did Dimak think Bean was? I'm thinking about how to get control of the situation here in Battle School, not how to save the world! "I don't think there is a solution," said Bean, buying time again. But then, having said it, he began to believe it. "There's no point in trying to defend Earth at all. In fact, unless they have some defensive device we don't know about, like some way of putting an invisible shield around a planet or something, the enemy is just as vulnerable. So the only strategy that makes any sense at all is an all-out attack. To send our fleet against their home world and destroy it."

"What if our fleets pass in the night?" asked Dimak. "We destroy each other's worlds and all we have left are ships?"

"No," said Bean, his mind racing. "Not if we sent out a fleet immediately after the Second Bugger War. After Mazer Rackham's strike force defeated them, it would take time for word of their defeat to come back to them. So we build a fleet as quickly as possible and launch it against their home world immediately. That way the news of their defeat reaches them at the same time as our devastating counterattack."

Dimak closed his eyes. "Now you tell us."

"No," said Bean, as it dawned on him that he was right about everything. "That fleet was already sent. Before anybody on this station was born, that fleet was launched."

"Interesting theory," said Dimak. "Of course you're wrong on every point."

"No I'm not," said Bean. He knew he wasn't wrong, because Dimak's air of calm was not holding. Sweat was standing out on his forehead. Bean had hit on something really important here, and Dimak knew it.

"I mean your theory is right, about the difficulty of defense in space. But hard as it is, we still have to do it, and that's why you're here. As to some fleet we supposedly launched – the Second Bugger War exhausted humanity's resources, Bean. It's taken us this long to get a reasonable-sized fleet again. And to get better weaponry for the next battle. If you learned anything from Vauban, you should have learned that you can't build more than your people have resources to support. Besides which, you're assuming we know where the enemy's home world is. But your analysis is good insofar as you've identified the magnitude of the problem we face."

Dimak got up from the bunk. "It's nice to know that your study time isn't completely wasted on breaking into the computer system," he said.

With that parting shot, he left the barracks.

Bean got up and walked back to his own bunk, where he got dressed. No time for a shower now, and it didn't matter anyway. Because he knew that he had struck a nerve in what he said to Dimak. The Second Bugger War hadn't exhausted humanity's resources, Bean was sure of that. The problems of defending a planet were so obvious that the I.F. couldn't possibly have missed them, especially not in the aftermath of a nearly-lost war. They knew they had to attack. They built the fleet. They launched it. It was gone. It was inconceivable that they had done anything else.

So what was all this nonsense with the Battle School for? Was Dimak right, that Battle School was simply about building up the defensive fleet around Earth to counter any enemy assault that might have passed our invasion fleet on the way?

If that were true, there would be no reason to conceal it. No reason to lie. In fact, all the propaganda on Earth was devoted to telling people how vital it was to prepare for the next Bugger invasion. So Dimak had done nothing more than repeat the story that the I.F. had been telling everybody on Earth for three generations. Yet Dimak was sweating like a fish. Which suggested that the story wasn't true.

The defensive fleet around Earth was already fully manned, that was the problem. The normal process of recruitment would have been enough. Defensive war didn't take brilliance, just alertness. Early detection, cautious interception, protection of an adequate reserve. Success depended, not on the quality of command, but on the quantity of available ships and the quality of the weaponry. There was no reason for Battle School – Battle School only made sense in the context of an offensive war, a war where maneuver, strategy, and tactics would play an important role. But the offensive fleet was already gone. For all Bean knew, the battle had already been fought years ago and the I.F. was just waiting for news about whether we had won or lost. It all depended on how many light-years away the Bugger home planet was.

For all we know, thought Bean, the war is already over, the I.F. knows that we won, and they simply haven't told anybody.

And the reason for that was obvious. The only thing that had ended war on Earth and bound together all of humanity was a common cause – defeating the Buggers. As soon as it was known that the Bugger threat was eliminated, all the pent-up hostilities would be released. Whether it was the Muslim world against the West, or long-restrained Russian imperialism and paranoia against the Atlantic alliance, or Indian adventurism, or ... or all of them at once. Chaos. The resources of the International Fleet would be co-opted by mutinying commanders from one faction or another. Conceivably it could mean the destruction of Earth – without any help from the Formics at all.