Given their first televised opportunity to question each other directly, the six Republican presidential candidates tonight produced a great show of chumminess--and a few pointed challenges to Texas Gov. George W. Bush.

On a night when the policy agreements were much more conspicuous than disputes, Bush, the early leader in the nomination race, was questioned sharply on liberalizing trade with China, the rising price of oil, Internet taxation--and, with humor, on his readiness to be president.

Utah Sen. Orrin G. Hatch, a long shot in the polls, made the last point explicit by suggesting to Bush that "you'd make a heck of a president after eight years" as Hatch's vice president.

Five of the six candidates were on the stage of the Orpheum Theater here, while Arizona Sen. John McCain participated by satellite from Boston. The senator faced none of the questions about his temperament that have been in the news during other recent appearances.

Conservative activist Gary Bauer subjected Bush to pointed questions on his support of normal trade relations and World Trade Organization membership for China. Citing abortion practices and religious persecution in that nation, Bauer asked why Bush supported "the Clinton-Gore" policy toward China.

"I don't," Bush said, but quickly added that "it is in our best interest" to open Chinese markets and "to be sure that the entrepreneurial class in China flourishes" there. By drawing China into trade relationships, he said, "you'll be amazed, Gary, at how soon democracy will come."

When Bauer said Bush was in effect condoning abuses of human rights in China, Bush replied that "if we turn our back on China, it will get worse." Helping China acquire the Internet and join in world trade will, he said, bring "that breath of freedom" with it.

Steve Forbes, who has been Bush's sharpest questioner, used his opportunity to press the governor on a potentially vulnerable point--his support of the oil and gas industry in his home state. Noting that a recent spike in oil prices after OPEC production curbs has caused supply problems for farmers in Iowa and families in New Hampshire--the first two states to vote next year--Forbes asked what Bush would do to get the prices down.

"Encourage more exploration," Bush said, adding that there were growing opportunities for natural gas to meet some of those energy needs. When Forbes pressed for more immediate action, Bush said, "The government doesn't control the price of oil--at least in America," implying that Forbes was calling for more federal regulation.

Bauer also took on Forbes, challenging the feasibility of his plan to convert Social Security to a system of private savings accounts for younger workers. Bauer said his mother wondered how the Forbes "scheme" could finance continued pensions for those approaching retirement age if most of younger people's Social Security taxes went into private accounts.

"We are a rich nation," Forbes replied, urging Bauer to tell his mother that if the Forbes plan had been put into effect decades ago, her monthly checks would be "two or three times" the size of those she is getting from Social Security. Bauer said it sounded as if Forbes thought Social Security was a bad idea--but Forbes said he wanted to improve the system, not undercut it.

McCain, whose absence tonight drew some criticism in his home state, used a question to Hatch to draw their difference with Bush on Internet taxation. McCain and Hatch favor making the current temporary moratorium on Internet taxes permanent, while Bush, like most governors, has expressed concern that shopping on a tax-free Web could erode the sales tax revenue base on which most states rely. Neither mentioned Bush by name, but aides said they expect the issue to become more important in future debates.

McCain's campaign finance reform effort was endorsed by Bauer but roundly criticized by Hatch and Alan Keyes, with the latter saying the Constitution protected unlimited contributions by individuals.

But McCain, in a friendly exchange with Forbes, argued that big money must be driven out of politics before the kind of sweeping tax reform Forbes has advocated could be enacted. In the first half of the 75-minute program, the candidates answered questions in turn from CNN correspondents. That gave them an opportunity to plug their favorite tax plans, their programs for improving schools and their approach to U.S. military intervention abroad.

All of them spoke in favor of education vouchers, with Bush stoutly insisting that he disagreed with the Clinton administration on the desirability of national pupil competency testing. Bauer and Keyes used the opportunity to call for restoration of prayer in public schools.

Those two and Forbes criticized U.S. military intervention in Bosnia and Kosovo, while McCain and Bush, as usual, spoke positively of the U.S. leadership role in the world, even while criticizing Clinton's policies.

The Feb. 22 Arizona primary looms as a serious test for McCain. Polls have shown him with a slight lead over Bush, who won the backing of Arizona Gov. Jane Hull. Forbes, though well back in the polls, has the same organization backing him that carried him to victory in Arizona in 1996 over Robert J. Dole.

Tonight was the second time in 96 hours that the six GOP contenders had debated, with many more such encounters scheduled in the weeks leading up to the Jan. 24 Iowa caucuses and the Feb. 1 New Hampshire primary.

Before the debate began, two members of the Arizona congressional delegation, Sen. Jon Kyl and Rep. J.D. Hayworth, told reporters that, despite the support Bush has from the governor, the overwhelming majority of Republican elected officials here are backing McCain. They also said that with his release of his medical records, the senator has answered all legitimate questions about his temperament, and, as Kyl put, "it's time to put an end to this"--the discussion of McCain's temper.

No one did raise it during the debate, although McCain made a joking reference to himself as "Miss Congeniality" of the Senate.

But cordiality was the keynote of the evening, with candidates first-naming each other and reaching for ways to compliment their rivals for their policy ideas and political accomplishments.

CAPTION: Sen. Orrin Hatch joked that Texas Gov. George W. Bush needed experience--as vice president.