NEW YORK -- For two weeks now, John J. Phelan Jr., the chairman of the New York Stock Exchange, has been pushed, pulled, threatened, pressured, glorified, criticized, scrutinized and in a hundred other ways subjected to the most trying fortnight of his life.

Through it all, in his tennis court-sized office on the sixth floor of the exchange's headquarters here, he has worked his telephone with the frantic energy of the trader he once was -- pushing not stocks or bonds, but solace and assurance to government officials, Wall Street executives, rival financial exchanges and the legions of investors who have descended on the NYSE in panicked waves.

Phelan's effort is widely regarded as one of the most important successes of the continuing stock market crisis. Facing the television cameras at critical moments during the past two weeks, he was seen as calm and poised. Backed by the NYSE's most powerful members, Phelan kept the exchange open in the face of what NYSE Vice Chairman Don Stone called "immense pressure on him from all sides" to accept a trading halt, which many believe would have exacerbated the crisis.

"I spent 25 years as a trader, so I'm used to controlling my emotions and I'm used to being under stress -- sometimes extreme stress," Phelan said. "I've spent most of my life trying to balance things."

And yet, however his role is eventually judged, Phelan seems determined above all else not to be remembered as the Pollyanna of this month's stock market panic.

In a reflective interview last week, Phelan said that he regards the market's worst collapse ever as an inevitable payback for a half-decade of financial and social excesses in the United States.

"We live in an instant-ese society. Everybody wants to put some hot water in a bag and have a nice cup of tea," he said. "Everybody wants to have all the nice things in life and have them quickly... .

"The free markets have been abused, and probably we're paying some of the consequences."

From the chief executive of the most prominent free market in the country, that may strike some as a surprising admission. But Phelan is a man of many seeming contradictions.

For example, he warned months before "Black Monday" -- the day the Dow Jones industrial average fell 508 points -- that speculative, computerized trading in stock index futures could lead to what he termed a "financial meltdown." But he was also the driving force behind the NYSE's 1980 decision, made in the face of stiff resistance from some exchange directors, to enter the stock futures trading business in competition with the major exchanges in Chicago, where most futures trading is conducted.

And as a manager, Phelan is regarded as a stern taskmaster, sometimes difficult to work for, but associates said that he also possesses an exceptional sense of humor and enjoys trading practical jokes with his top aides. On Phelan's desk sit carved statues of an abominable snowman and a yak, supposed gifts from the "chief executive llama" of the New Yak Stock Exchange, a fiction invented by a former aide who enjoyed mountaineering in the Himalayas.

Phelan's many allies on Wall Street regard these seeming inconsistencies as evidence of his pragmatism, a quality that has been much in demand during the last two weeks. Phelan, they note, is a devoted student of Machiavelli, the preeminent philosopher of practical politics.

His attitude toward computerized stock futures trading -- which has become the most controversial issue to arise from the market crisis -- is cited by Phelan's supporters as strong evidence that the NYSE chairman's decision-making during the panic has been guided primarily by a devotion to solving problems.

Not everyone sees it that way. The NYSE's critics, particularly officials of the Chicago exchanges and their political allies, have suggested that Phelan used stock futures and computer trading as a scapegoat to shift attention away from difficulties caused by the NYSE.

Either way, the issue provides one instructive example of Phelan's leadership style and of his willingness to take decisive action during the market crisis, even if that action is controversial or goes against positions he has staked out in the past.

Until this month's crisis, Phelan's five-year tenure as NYSE chairman -- a position he attained after holding various jobs at the exchange over 25 years -- had been defined by his aggressive defense of the Big Board against growing competition from other exchanges and the advance of computer technology, which threatened to make the NYSE's "auction" system of stock trading obsolete.

Phelan met those challenges by pushing tradition-bound NYSE directors and members to accept a $100 million automated computer system that speeds stock trading orders to the exchange floor. And, worried by the aggressive move of the Chicago financial exchanges -- particularly the Chicago Mercantile Exchange -- into trading of new stock options, stock futures indexes and other so-called derivative instruments, Phelan successfully urged the NYSE to start its own rival futures exchange.

But earlier this year, the NYSE chairman began to voice doubts about futures trading. He said that use of stock index futures by large institutional investors was contributing to market volatility and he warned of a possible meltdown.

By and large, Wall Street was not ready to listen to Phelan's message. "Meltdown was John's comment, and he took untold abuse in the industry," Stone said.

In an attempt to build a consensus on the issue, last summer Phelan commissioned an NYSE panel to study the problem and make recommendations about reforms. That study will likely be released before the end of the year.

Stock index futures, notably the popular Standard & Poor's 500 index traded on the Merc, allow investors to speculate on the overall movement of the New York stock markets. Large investors equipped with sophisticated computer programs use the index futures to protect themselves against losses in a down stock market. Through a technique known as "index arbitrage," they also use computer programs to profit from the differences between futures prices in Chicago and stock prices in New York.

When panic selling hit the world's financial markets on Black Monday, Oct. 19, Phelan regarded computer-driven futures and stock trading as a significant part of the problem. As early as Oct. 20, he in effect pulled the plug on the NYSE's $100 million computer system and he urged member firms to curtail futures trading.

Several high-ranking Wall Street executives interviewed last week called Phelan's decisions courageous, noting that there was no clear consensus among member firms or in Washington over what should be done about computer trading while the panic was on.

"I think that John has always recognized that the exchange has to let its business develop with changing times and that really to protect its {stock} market has had to go into futures and options," said Roberta Karmel, a member of the NYSE board.

"At the same time, I think he has been acutely aware -- much more so than other leaders in the regulatory area -- that these products as presently traded have a potential for volatility that is a great danger to the market."

"He's had an incredibly difficult task and he's sort of made all the right moves," said Peter T. Buchanan, chief executive of First Boston Corp., a leading Wall Street investment firm.

Phelan acknowledged that he was in some ways prepared for the decisions he faced because in previous months, when he began to voice his meltdown scenario, he also thought about how he might respond if his prophecy were fulfilled. But he said he was hardly prepared for the magnitude of the crisis that struck.

"The reality of it is that when you think it's coming, you hope it's not on your watch, number one. And number two, it was probably even greater than when you thought about it coming," he said.

Phelan, who is described by associates as a serious reader of history and literature, said the lessons he has taken away from the stock market crisis are ones that he already knew, but about which everyone needed to be reminded.

"I suppose you learn and relearn over again ... that psychology still plays as much of a role in the market as it's ever done. No matter how smart the people you get in the market, they all seem to do the same things they've done historically," he said.

"You could have seen it coming, but nobody believes it's coming until you're there," he continued. "Could we have done something? Yes. But history says you don't. History says you go through the excesses. This may in fact just be an early warning."

Phelan's criticisms of financial excess in the 1980s apparently are not driven by any partisan impulses. He has never been active in party politics and close associates said they did not know if he has even belonged to any political organizations.

But Phelan, who has been in close contact with the White House, Treasury Department, Federal Reserve Board and Securities and Exchange Commission during the crisis, is certain to be drawn into the political debate over possible financial market reform that is already under way in Washington. Last week he testified about the market crisis at a closed session of the House securities subcommittee.

Phelan said that one specific lesson that has emerged is that "there isn't enough capital around in all the markets and in all the market participants. We've got to find out how to get more... .

"It raises long-term questions about what markets are and how much volatility should be in them and how much leverage."

Still, the NYSE chairman said he hopes that Congress and the administration "will not politicize the process. While {the stock market} may have been brought to its knees, it was back on its feet in a couple of days.

"We can take pride in a lot of things that have been done... . I don't think this is a time for beating of chests."