Was there anything else?

Yeah, there was. His voice softened: "I'm sorry about Henry and Emily. I know you and they were close."

"Thank you, Mr. President."

"I'll expect you to stay on as chief of staff. At least until we get through this."

"Yes, sir."

He broke the connection, wandered back into the passenger cabin, where everyone pretended to be busy reading. "Everything okay, Mr. President?" Evelyn asked.

They'd all gone formal on him again. And maybe it was just as well. He wondered how much Lincoln would have accomplished if everyone in the neighborhood had called him Abe.

"Fine," he said. "We're doing fine."

Which reminded him. He went up the ladder-he was getting good at zero-g moves now-and came in behind Saber. "Hello, pilot," he said.

She raised a hand without looking around. "Hello, Mr. President."

"I understand we're not going to Pluto after all," he said.

"Oh," she said. "You know about that. No, we'll be okay. We were never at risk."

He slid into the copilot's chair. "You're sure?"

"Yes, sir," she said.

"Anything I ought to know about?"

"No, Mr. President."

"If there's another problem, I'd like to be informed," he said.

"Yes, sir. I didn't think of it as a problem. I mean, I knew they had the Lowell in reserve." She smiled up at him. Saber was, he decided, a beautiful woman. Somehow, there hadn't been time to notice before. "I thought you had enough to worry about. Getting the Micro back was my job."

"Do we have any fuel left at all?"

"We've got a couple hundred pounds. Not very much. I'm trying to save it."

"Okay. What's the drill on the rescue?"

She relaxed a little. "Lowell will catch up with us around four. We'll transfer over and cut the Micro loose. They haven't sent me an ETA yet, but I'd guess we'll get back to the station by late evening. That's only a guess. I don't know what the capabilities of the Lowell are."

Charlie looked at the myriad blinking lights and telltales on the Micro's displays. "Can we see the Possum from here?"

She touched a key, and the rock appeared on a heads-up screen. "That's the view from one of the satellites."

The media descriptions said the Possum looked like something that had been cut in half. One side was flat, the other curved and rugged. It was more oblong than spherical, almost resembling a club. He was glad that idea hadn't occurred to anyone in the media. He watched it tumbling slowly across the display.

Saber's fingers moved over the keyboard. "Here's something to compare it with." An image of the Micro blinked on. It shrank until it was almost invisible against the object. "That's us." She pressed another key, and a series of micro-icons lined up along the length of the rock. "There are sixty-one of them," she said. "End to end."

"And how big are we?"

"Twenty-eight meters and change, blister to treads. We're pretty compact."

"We'll be well rid of the thing," he said.

The Possum exerted a near-hypnotic influence. He watched it turning, watched, on another screen, the blue globe of Earth.

The second image, Saber explained, was from the Micro's telescopes.

The distance between the vice presidency and the office of the chief executive, Charlie was discovering, is measured in light-years. It might be that no one really understands that who hasn't stood on both sides of the chasm. A few hours ago he was only worried about saving himself. That concern now seemed almost trivial.

The third decade of the twenty-first century had, until a few days earlier, been a good time for the planet. A hundred million Chinese were driving cars, almost everyone agreed that military incursions were in bad taste, the old economic cycle of boom and bust appeared to have been tamed, and the great powers had discovered that collaboration was more fruitful than competition. Technology was providing better lives for almost everybody. Science was forging ahead, and people now lived longer and stayed younger than ever before. Most cancers were curable; powersats supplied virtually unlimited energy; and the long struggle to reverse environmental damage had finally turned the corner. In the United States, racial tensions had been steadily easing, GNP was up every year, crime rates and population growth were down.

This is not to say there were no problems. There were far more people than the world's natural resources could comfortably support, and ancient traditions and religious groups fought every effort to reduce the numbers. There was still too much crime, and too much of it violent, particularly in Russia, the United States, and China. A recent survey of American adults by USA Today suggested that three-eighths of the population were functionally illiterate. This was the highest ratio of any industrialized society, and it continued to climb steadily. The advantages of participating in the global communications network were still not available to a quarter of the U.S. population, and to more than a third of those living in other Western nations. Every major government carried a staggering burden of debt.

These were the problems a Haskell administration would have reasonably expected to confront. Anticipating the possibility of victory in the fall, Charlie had already staffed out work and formulated some ideas on his own. He'd talked to the people on the front lines, teachers and parents and cops and emergency room physicians and first-line supervisors in a wide range of occupations. He thought he was ready to assume the burdens of the presidency with a series of initiatives to attack these problems across a broad front.

As things had turned out, he could hardly have been less prepared.

Saber frowned and touched her earphone. "Wait one," she said and looked at Charlie. "For you, Mr. President." But his lamp hadn't lit up, so the call wasn't coming in on his private channel. "Do you want to talk to a Wesley Feinberg?"

"I've got it." Charlie opened his cell phone. He'd never met Feinberg, but he knew him by reputation. And Al had briefed him on his part in the planning. Called him a troublemaker. "Good morning, Professor Feinberg. This is Charles Haskell."

"Mr. President." The voice was strained. "I've been trying to get through to you for hours. Are you still planning to execute the nuclear strike against the Possum?"

"Yes," said Charlie. "Of course."

"Don't."

Charlie's heart sank. "Why not?"

"We don't know enough to be able to change its trajectory. That's what we really need to do. But we don't know how."

"So we give it a try. What's to lose?"

"What's to lose? Mr. President, you blow it apart and you'll create a cloud of radioactive particles and debris that would be just as likely as the Possum to come back around and hit us later. Except that, if it were to happen, the consequences would be even worse."

"Worse how? My information is that the Possum would kill a few more millions. Maybe send us back to a dark age."

"Mr. President, a healthy radioactive cloud would have a good chance to kill everybody on the planet. I'm talking about an extinction event."

Charlie visualized a storm of hot pebbles ripping into the global landscape and the oceans, hot particles settling into the atmosphere, hot rain pouring down out of diseased clouds. "Why didn't you tell this to Henry?"

"I did. Or I tried to. I was talking to him when we got cut off. I think it was probably at the time his helicopter went down."

"What did he say?"

"He didn't have a chance to say anything." Saber was watching Charlie. "You must stop the attack," Feinberg went on. "It will gain nothing, but it raises the stakes dramatically for us if it comes down."

"But it might not come down. Is that right?"

"There's no way to be sure."

"For God's sake, Feinberg, isn't there a way to find out?"