The timing could not have been more perfect if it had been planned. Entering the presidential race, from one side of the stage, Gov. George W. Bush of Texas, the embodiment of the Republican establishment. Crashing in from the other, Patrick J. Buchanan, the scourge of the self-same establishment.

That Bush announced his presidential exploratory committee in Austin on the same day Buchanan was declaring his candidacy in Manchester, N.H., ensured that this coming nomination struggle will be anything but dull. It is all the more wondrous because Buchanan, by running for the third straight time, has the opportunity to submit the younger Bush to the same acid-bath treatment he administered to President George Bush in 1992.

Buchanan didn't beat Bush in the New Hampshire primary that year -- or anywhere else for that matter. But by winning 37 percent of the votes in the leadoff primary, compared to Bush's 53 percent, he exposed the incumbent's vulnerability on economic issues in a way that Bill Clinton and Ross Perot were both able to exploit in November.

The key for Buchanan in his first race was combining the votes of two disparate groups of discontents: social-issue activists, especially antiabortion folks, and working-class voters battered by the severe recession then plaguing all of New England.

Gov. Bush was an unhappy spectator in 1992, when he was riding herd on his father's campaign as an untitled adviser. Next to Perot, Buchanan may be No. 1 on his personal list of "people we don't invite to dinner."

But ostracism does not faze Buchanan. He was back in 1996, in far better economic times, with a message broadened to include bashing imports, immigrants and foreign military commitments. He summed it up in the historically freighted words "America First." This time, he won New Hampshire, exposing Bob Dole as the fragile candidate he proved to be against Clinton.

They are an interesting contrast, Bush and Buchanan. Both grew up in privileged circumstances, private schools and all the rest; both had rebellious youths; and both have made lots of money on their own. They have been saved from snobbism by their political experiences.

Buchanan was genuinely affected by the stories he heard in 1992 from New Hampshire families struggling with the threat and reality of layoffs and worried about keeping their homes and health care during the last recession. The ever-stronger populist strain in his rhetoric goes back to those conversations.

Bush, as a Texas candidate, has spent more time in the Mexican American and African American communities than ever before in his life and has absorbed the intensity of the struggle of those families to make better futures for their children. The genuine passion he and his wife, Laura, express about education as the "way up" for those youngsters comes out of those experiences.

The prospective rivals have very different policy views. Buchanan would build a fence along the border with Mexico; Bush embraces ever-closer ties with the nation to our south. Bush favors open trade; Buchanan is proudly protectionist. Buchanan is a litmus-test Republican when it comes to abortion. Bush is pro-life, but clearly of the "big tent" school which wants to welcome pro-choice Republicans.

Bush has been embraced by many of the big names in the GOP, notably his fellow governors. Buchanan is anathema to them; they rallied behind the politically wounded Dole in 1996, in large part because they thought Buchanan spelled disaster for the party if he were to become the nominee.

The Bush-Buchanan dichotomy is so perfect, in fact, that it poses a serious problem for the other eight to 10 people who will make up the likely Republican field. Some, such as Steve Forbes, can finance their own campaign. Others, such as Lamar Alexander and perhaps Dan Quayle, have already established networks of supporters. Elizabeth Dole likely has the potential to mobilize many women, not all of them Republican activists.

But even if there were enough money and workers for all of them -- and for such other candidates as Sens. John McCain and Bob Smith, Rep. John Kasich and conservative activists Gary Bauer and Alan Keyes -- there is a finite amount of press and television coverage available.

Elizabeth Dole commands considerable media attention, because of her name, her renown and her gender. But the potential of a second Bush-Buchanan brawl would be so tempting that the other campaigns would have to be inventive to lure reporters and cameras to the sites of their events.

Bush-Buchanan Round Two in New Hampshire. It doesn't get any better than that.