But which campaign will go “haywire”? Is it McCain’s remarkable (and deceptively shrewd) insurgency–or George W. Bush’s increasingly vitriolic Establishmentarian counteroffensive? The Republicans’ South Carolina primary this Saturday has turned into a dirt-in-Dixie classic, in which the two candidates display their moral indignation while their grizzled GOP consultants–who know all the tricks in the book–go at each other like roosters in a Carolina cockfight.

Even as they claw at each other, the candidates claim to be seeking the high ground. McCain, the scrappy confrontationalist, has turned pacifist, dramatically forswearing the use of negative ads–forever. Why? He already got his digs in against Bush on Social Security. Two television spots McCain aired in South Carolina, which attacked Bush personally, backfired because they were seen as too mean.

More important, McCain realized that he was jeopardizing his most valuable asset, his good-guy image. McCain is wooing Independents and Democrats, and he can’t wax indignant about Bush’s tactics unless he cleans up his own act. Three days after South Carolina comes Michigan, another “open” primary where McCain is close in the polls and needs good-government votes to win. Flush with online cash and new momentum, he is looking long term, and could survive a narrow loss this week. “We could match Bush ad for ad,” said Rick Davis, McCain’s campaign manager. “But we might win the battle and lose the war.”

Bush has turned his own strategy upside down. Mr. Geniality has become Mr. Mean. Why? Nothing like the prospect of a hanging to concentrate the mind. His $70 million war chest is rapidly shrinking (he may have less than $18 million left after this week, party insiders told NEWSWEEK). The Republican power elite that backs him is getting antsy. A loss Saturday could be fatal.

So Bush is betting his ranch on a strategy of jihad. Bush insists that he is the one on high ground. McCain, he points out, was the first to “go negative” and the first to become personal by comparing Bush’s regard for the truth to Bill Clinton’s. “It’s an old Washington trick,” said Bush: blast the other guy and call a truce. Wooing hard-core conservatives, Bush is flooding the state with TV ads, radio spots, direct mail and calls. Some of the telephone attacks are savage, portraying McCain as a hypocritical, temperamental insider who is soft on abortion, partial to Las Vegas gambling interests, in thrall to Big Labor and who has a budget plan that would cut donations to the nation’s churches. “It’s not pretty, but it’s going to work,” vowed one of Bush’s top advisers.

The new NEWSWEEK Poll shows why both campaigns are desperate. The race is too close to call. Bush leads, 43 to 40 percent. He leads among Republicans by a 53-32 percent margin, but McCain leads among everyone else (Independents and Democrats) by 49 to 32 percent. The outcome depends on turnout: the bigger it is, the more likely McCain is to win. There’s no simultaneous Democratic primary, making the GOP event the only game in town. He has his eye on Independents elsewhere, NEWSWEEK learned. If he wins the GOP nomination, a top aide told NEWSWEEK, McCain will seek the Reform Party’s nod–if there’s a Reform Party left to offer it.

Appropriately for the Bible belt, McCain described his change of tactics in road to Damascus terms. The turning point, he said, was an incident in Spartanburg, S.C. There, a woman told him that her 14-year-old son had taken a call from a supposed polling firm. After asking some perfunctory questions, the caller blasted McCain as a “cheat, a liar and a fraud.” The caller, she said, was a “push poller”–using the insider’s term for the practice of spreading dirt on an opponent in the guise of a survey.

Later, in New York, McCain said he’d been so affected by the boy’s trauma that he’d decided to abandon negative ads. It was a stirring story–which Bush staffers immediately derided. They had no proof but suspected the McCain campaign of a setup. “Kind of a technical term for a lady from Spartanburg to use, don’t you think?” asked Karl Rove, Bush’s campaign manager.

Not necessarily. In South Carolina, tactics may be trumping substance. McCain had started the week determined to counter Bush’s aggressive new strategy. His Beltway-based advisers, many of whom had worked in 1996 for Bob Dole, feared that their man would be chewed up–the way Dole was by Clinton, and Bill Bradley was by Al Gore last month. “I wasn’t going to allow that to happen to me,” McCain told NEWSWEEK. But the campaign’s response ads caused a backlash even among McCain’s own supporters. “I think they were a bit over the line,” said Republican Congressman Lindsey Graham, a leader of McCain’s campaign in the state. He told McCain so Wednesday night. The ads were soon pulled.

While McCain plays martyr, Bush must ingratiate himself with core GOP voters–by citing his own virtues and demonizing McCain. He also has to dull McCain’s glow among Independents and Democrats, and hope they’ll be too discouraged to turn out. Bush dismisses his foe as “Chairman McCain,” but doesn’t spend much time attacking him on his own. Instead, the governor now mimics his rival, offering himself to voters as a “reformer with results,” with a solid record of accomplishment in Texas on issues such as education, legal reform and taxes.

Bush has undergone a personal makeover as well. He’s ditched his starchy stump speech and left the lectern behind. He appears like a stand-up comic in front of a mike stand, fielding questions from all comers. He’s even made an attempt to befriend the press corps, bowling oranges down the aisle of the campaign plane.

The son and grandson of reticent Episcopalians, Bush becomes more churchy by the minute. Some of his events resemble those of Sen. Jesse Helms, the Republican next door in North Carolina: gatherings of hard-core GOP faithful in dusty, roadside spots city folk rarely see. At a “fish camp” restaurant in tiny Catawba last week, Bush sounded like a parishioner at a prayer meeting. “I’ve got a personal faith,” he told the guests who had been attracted by the prospect of a Bush-funded free lunch. “Billy Graham helped a seed to be planted in my life, like a mustard seed. I stand before you as a sinner who sought redemption.”

While Bush worked the fish camps, his team and its allies worked the media. A new TV ad brands McCain a phony, a champion of reform who is hungry for corporate PAC donations (including those he got at a big Washington fund-raiser last week). Another ad takes on McCain’s earlier ads, with Bush himself accusing his rival of hitting below the belt.

But TV is the gentle stuff, as Bush himself acknowledges. Late last weekend C-Span caught Bush chatting with a supporter. “I have no explanation why some of the religious conservatives are with [McCain],” said State Sen. Mike Fair. “Y’all haven’t even hit his soft spots.” “We’re going to,” Bush replied, but added that he’s “not going to do it on TV.” That’s where radio and telephones come in. Allies in the right-to-life movement are running a radio spot attacking McCain on abortion. In New Hampshire, the ad notes, McCain said teasingly that he might want to name former senator Warren Rudman attorney general. “Who’s this Warren Rudman?” a female voice asks in the radio spot. Why, he’s a guy who once wrote that Christian conservatives were “zealots” who would ruin the GOP.

There’s more on the way, NEWSWEEK has learned. This week a fundamentalist group will launch an attack on McCain’s tax-and-budget plan, which would require that stock or items donated to charity be valued at their purchase price, not their presumed current market price. A group of pastors will come forward to declare that the proposal would cut the flow of church donations. In another ad likely to hit the gospel radio waves, Bush allies will note that the Las Vegas Sun once praised McCain for his legislative work on behalf of gaming.

But the toughest stuff is over the telephone–the bloodiest trench warfare in politics because it is the hardest for the other side to track. Bush’s polling firm made at least 300 calls that included harsh “questions” about McCain without identifying who was paying for the poll. Those calls seem to have been classic “push polling,” but Rove claimed that they were designed only to probe for McCain’s weak spots. In thousands of other “advocacy calls,” the Bush campaign identifies itself.

The Bush campaign denies that it is saying nasty things, but South Carolina is full of echoes of these calls. Jennifer Prather, a 19-year-old with muscular dystrophy, got one. She said she was leaning toward McCain–then got an earful about how McCain was a liar and a cheat. Vicky Ratley of Greenville, a McCain supporter, also got a call. When she stated her preference, the caller asked: “Are you aware of John McCain’s temper?”

McCain exuded an air of calm as the barrage continued. In fact, as he knew, his own handlers had caused their share of such calls to be made over the years–though they insist not this time. “We’re the good government campaign,” declared Davis. He didn’t seem entirely pleased at the prospect. But his boss had made his decision. All McCain could do was be hopeful–if he dared to let himself feel that emotion.