BALTIMORE -- One of Tip O'Neill's favorite subjects of palaver was his conviction that the pendulum of national politics swings in a 20-year arc.
Forty years ago, a young Irish charmer wrested the White House from Republican rule by galvanizing the young, energizing the Democratic base, and seducing votes from skeptics and Republicans with a cocktail of themes tied to America's destiny. Twenty years later, another Irish-American, nearly 30 years older but just as charismatic, ejected the Democrats from power with the patter of patriotic virtues and the beguiling promise of tax cuts that cut across party lines.
Now comes another political cross-pollinating Celt, a maverick Scottish -Irish Republican with a zest for political combat unmatched in recent annals. Like Jack Kennedy and Ronald Reagan, John McCain's alchemy attracts voters normally opposed to some of his positions and cuts across the fault lines of contemporary politics.
The sword-swinging leader of the Braveheart crusade to purge corruption from the political money system fits neatly into the timetable O'Neill used to cite.
What he did Tuesday, winning the Michigan primary with the votes of hundreds of thousands of independents and crossover Democrats, was the modern political equivalent of plucking Excalibur from the frozen stone of partisan rigidity. By confounding the Republican establishment that had too-hastily embraced Prince George of BushLand, McCain sows panic in the leadership of the party he needs to nominate him.
The mantle of ''inevitability'' has fallen from George W. Bush's shoulders. The way Bush won South Carolina - casting his lot with the likes of Pat Robertson and the antiabortion zealots - dooms any realistic Republican chance of capturing California and New York in November and imperils Republicans in those prochoice states who are further down the ticket if Bush is the nominee.
Bush's recourse to the voodoo economics of promising huge tax cuts is drowned out by McCain's blaring brass band. As H.L. Mencken wrote wickedly of the Harry Truman campaign of '48, the wooing of the unwary was wonderful to watch: ''If there had been any formidable body of cannibals in the country, he would have promised to provide them with free missionaries fattened at the taxpayers' expense.'' Bush is befuddled by the slow sales of his tax-cut pitch.
Given the terrain ahead and the level of commitment to Bush by party apparatchiks, and the barring of independents and crossover Democrats from many contests ahead, you'd still have to make Bush's odds slightly better than 50-50 for the nomination.
McCain has gone from a 1-in-100 shot last year, to 1-in-10 after New Hampshire, to 3-in-10 or better. Winning California is crucial on March 7, for all 162 delegates there, nearly one-sixth of the total of 1,034 needed to nominate, go under a winner-take-all formula, with only GOP ballots determining the delegate apportion.
The McCain phenomenon has gone national. New Hampshire gave it life. South Carolina tried to snuff it out. Michigan rolled back the stone from the crypt. The McCain contagion is drawing the young, disaffected, and those longing for a different breed of politician. And the GOP party establishment does not know how to react to the explosion of interest.
''They're coming in, they're giving checks, they want bumper stickers, they say `Anything I can do?''' Tom Trimarco, a veteran Republican spearcarrier volunteering in McCain's bustling Massachusetts headquarters in Quincy, estimated that 75 people had walked in yesterday morning by noon.
Typical of the fervor for the Navy fighter jock who survived three different plane crashes is a fellow named Ed, a native of East Boston now living in the suburbs, who said yesterday: ''I'm a lifelong Democrat, never gave any politician any money before. I'm going through a divorce right now, my money's on hold, but I liked this guy McCain for some time now. I send him 20 bucks, 25 bucks; there are many people like myself. We believe in this man. Those voters in South Carolina are a bunch of blockheads. Michigan was people like me.'' Ed believes.
But the Republican leaders in the Senate tremble at the thought that McCain might seize the reins. Not since 1964, when Barry Goldwater challenged the Eastern establishment, has the party faced such a wrenching turn. Reagan fought Nelson Rockefeller, President Ford, and George Bush the Elder to win his White House time. But McCain's terrible swift sword of campaign finance reform threatens the grip of Senator Trent Lott, the Senate majority leader, and Senator Mitch McConnell, the brainy collector of special interest money and arbiter of cash handouts to campaigning Republicans.
If McCain wins the nomination, the GOP would be turned on its head. The party has a champion with proven ability to draw votes across the board. The fact that it does not embrace him tells you all you need to know about the Republican leaders: They're afraid of the man with fire in his belly for real reform.
David Nyhan is a Globe columnist.
