Probably 130 million Americans will vote in this year’s presidential election, but the last six weeks of the campaign is not about them. It’s about only a few hundred thousand voters. They are the Libertarians, Greens and undecideds who live in about 10 swing states. These are the ones who, in this very tight election, will make the choice for the rest of us between Donald Trump and Hillary Clinton.

And that was what the presidential debate Monday night was also all about. By this measure, both candidates failed to do what they needed to do to draw these swing voters into their orbit. Their failures were very much consistent with their characters, but Trump’s failure was glaring whereas Clinton’s was modest. While her stern absence of humor or personal anecdotes failed to establish a personal rapport with voters, his anger, defensiveness and contradictions showed he was in command of neither the issues nor himself.

Both candidates did well enough to protect their base of slightly more than 40 percent of the electorate; neither reached out effectively to secure the support of the remaining 15 percent or so. However, if Clinton is able to lock in only a couple of percent of the swing voters, it would be sufficient to win the election, and her performance was strong enough for her to do that. Before the debate, Clinton was leading Trump in national polling averages by a little more than 1 percent. It will be interesting to see what the new batch of polls shows when released this coming weekend.

Four factors drove Clinton’s relative success in the debate.

First, while it was clear from their recitation of facts and non-facts, real and distorted data, that both candidates had prepared for the debate, Clinton, as is typical of her, had prepared far more thoroughly. The debate sometimes reminded me of the Sinhalese adage, “A lie well told is worth a thousand facts.”

Second, Clinton did what she had intended to do, which was to take the fight to Trump. She called him out on his most controversial comments about women, blacks, nuclear weapons, refusing to defend NATO allies and lowering taxes on the wealthy. On these and a host of other issues, Trump struggled to justify what he had said—sometimes by simply denying he had made comments that were indisputably on the record. At one point he even made the mistake of getting into a debate with moderator Lester Holt—rather than with Clinton—over his 2002 support for invading Iraq.

Third, Trump failed to answer several of Holt’s questions and Holt—while for the most part eschewing fact checking—persisted in trying to get answers that Trump sought to avoid giving.

Fourth, Trump didn’t stick to his agenda. He began with an effort at restraint and courtesy, repeatedly addressing his opponent as Secretary Clinton. A clear signal that he was abandoning this strategy occurred in mid-debate when he switched to calling her Hillary. Meanwhile, she consistently called him Donald.

The initial issue dealing with trade played to his strength, and he took full advantage of it, repeating again and again and again the mantra that he would stop jobs from migrating overseas. However, he was unable to answer Holt’s question of how he would return jobs that had already left.

On this issue, Clinton suffered from her inability to admit the obvious, that she had changed her position from pro- to anti-free trade. On the defensive, she tried and failed to explain away the obvious.

But that was pretty much the end of the good times for Trump. Most of the subsequent questions pricked Trump’s weaknesses or were phrased in such a way that they put him on the spot. For example, the key question on how to combat terrorism focused on domestic terrorism by U.S. citizens or legal residents. There was no discussion of Trump’s iconic topics: stopping illegal immigration, building a wall on the Mexican border and deporting 11 million undocumented workers.

But there was extensive discussion of Trump’s refusal—unlike every other presidential candidate in modern history—to disclose his tax returns. At one point Clinton charged the secrecy was because he hadn’t paid any taxes, and Trump didn’t deny it. Looking for a way out, Trump finally said he’d release his tax returns if Clinton released 38,000 emails.

Holt shot back, “Then it’s negotiable?”

Trump then contradicted what he had just said: “No, it’s not negotiable.”

The debate, the first of three between the candidates, had the largest audience of any event in this or any other campaign. The most-watched debate ever was in 1980 between Ronald Reagan and Jimmy Carter, with 80 million spectators. (By contrast 114 million watched the 2015 Superbowl and 1 billion the World Cup.) This year’s debate, before an audience predicted to exceed 100 million, was probably Trump’s last best chance to seize the lead.

On the eve of the debate, 75 percent of likely voters said they planned to watch the debate and 12 percent said it was somewhat likely or very likely that it would affect how they voted.

While the race has tightened over the past month, the great majority of polls still show Clinton very slightly ahead. It is hard to see how Monday’s performance will help Trump win over the undecided and third-party voters without which he cannot triumph.

The run-up to the debate featured headlines and verbiage worthy of a war or some other kind of earth-shaking violence. All the pugilistic metaphors reminded me of the great Ali-Foreman world championship boxing match in Kinshasa before 60,000 fans—the famed “rumble in the jungle.”

In the event, Monday’s conflict was a bit subtler—but only a bit. It was still real conflict between two skilled punchers and counterpunchers. The question was which would emerge as Ali—fast, tough, nimble and graceful. Clinton is not Ali, but she came closer than Trump. Given the vast differences in the candidates’ personalities and policies, it is not overstating the case to say the future of not just the United States but the world is at stake.

In 2008, some 131 million Americans voted in the largest turnout in history, and in 2012 some 124 million. Given the closeness of the polls and the size of the stakes, the turnout this year could exceed any election in the past. Early voting is about to begin in many states. In New Mexico the deadline to register to vote is Tuesday.