hink of it as two planets on a collision course, one that could rip away moons, rearrange orbits, and reorder gravitational fields.
Now name the planets Al Gore and Bill Bradley and you have the next stage of their campaign for the Democratic presidential nomination.
Both camps are keenly aware of - and privately worried about - any uprooting of their cornerstone vote. But the crisscrossed constituencies that currently characterize the contest make that prospect very real.
Consider the biggest single development in the race so far: Bradley's success in consolidating college-educated voters.
That more than anything else explains his rise to parity with Gore across New England and in New York. The most recent Boston Globe poll of New Hampshire, done late last month, shows just how powerful an indicator education level has become.
Those with a high school diploma or less favor Vice President Gore 62 percent to 24 percent, while those with a college degree or graduate degree favor Bradley, the former three-term US senator from New Jersey, 55 to 31 percent.
''It is far and away the biggest demographic difference,'' says Gerry Chervinsky, the Globe pollster.
And it is a difference that seems to hold across New England and into New York. For example, a University of Massachusetts survey of Bay State voters last month found the Democratic race deadlocked at 38 percent for both Gore and Bradley among those with a high school education or less.
But among voters with a two-year college degree, Bradley led Gore 42 to 33 percent; among those with a four-year degree, Bradley's lead increased to 51 to 28 percent.
That vote has proved a powerful base before. The same basic group almost overnight transformed Gary Hart from asterisk to avalanche in New England during his 1984 race against Walter F. Mondale for the Democratic nomination. And it's a cohort that, though split, still helped catapult Paul Tsongas onto the national stage of Democratic presidential hopefuls in 1992.
''What we think of as the Bradley surge is largely explained by how these voters have found Bradley around the time of his announcement,'' said Ralph Whitehead, who teaches journalism at the University of Massachusetts at Amherst. He has dubbed this group '' bright collar workers.''
How important will they be? In New England, very.
About 27 percent of New Hampshire residents over age 25 have a four-year college education or more, but in the last contested Democratic primary, in 1992, that group cast 50 percent of the votes. By contrast, 47.5 percent of New Hampshire residents over age 25 have a high school education or less, but in the same primary, that group cast only 26 percent of the votes.
''In effect, Bradley's initial demographic base casts two votes per voter and Gore's initial base cast half a vote per voter,'' said Whitehead.
But now for the disconnect. Hart and Tsongas, notable past beneficiaries of the bright collar vote, campaigned as neo-liberal reformers questioning their party's old-line liberal dogma. Thus they were naturally in sync with a group of voters wary of rigid ideology, favoring fiscal restraint, and resigned to the discipline of markets and rapid change of the information economy.
Democrats had to realize, Tsongas said again and again, that the economy wasn't an ATM machine that could be tapped - or taxed - endlessly to pay for social programs without worrying about generating new wealth.
That's hardly the Bradley message, at least so far. Instead, he's running as the voice of old-fashioned liberal values.
His hallmark proposal is a near-universal health care plan that, by the candidate's own estimate, would cost at least $65 billion a year. Add to that a $10 billion a year plan to fight child poverty, a $2.6 billion proposal to help working families, and a $1.3 billion plan for agriculture. Then, of course, there's his call to register all handguns and provide for publicly financed federal elections.
Bradley's emerging role as progressive paladin was underscored last week at Saint Anselm College in Manchester, where he received the endorsement of Robert Reich, President Clinton's first Labor secretary and one of the nation's best-known liberals, who said he was drawn by Bradley's progressive vision.
Crediting Clinton with fixing the economy and turning deficits to surplus, Reich argued that a strong economy and brimming treasury now permit bold strokes ''to tackle the nation's unfinished agenda.''
Which is just the way Bradley sells himself. Asked at the same event if the nation could really afford such an expensive health care program, Bradley sounded a certain trumpet.
''In a world with a trillion-dollar surplus ... we can afford that,'' he insisted. ''If not now, when? If not us, who?''
And perhaps the nation can - though the very presumption of a trillion-dollar surplus assumes the federal government can stay within spending targets universally seen as unrealistic.
Still, the point is that Bradley's politics are hardly the fiscally cautious neo-liberal nostrums of previous candidates who have caught New England's bright collar comet. Instead, his proposals reflect policy goals that should make him an easy favorite of the Democrats' traditional base of lower middle-class, working-class, and minority voters.
But those groups are much more inclined to back Gore, notes Andrew Kohut, director of the Pew Research Center for the People and the Press, while Bradley, ''is more appealing to upscale Democrats at this point than downscale Democrats.''
Two things explain the disconnect.
Right now this race remains more about atmospherics than issues; as often as not, Bradley supporters like their candidate less for specific issue positions than because his mature, thoughtful, authentic manner seems to make him a perfect antidote to the Clinton years.
As for Gore's vote, it's one he has largely inherited from Clinton. But the worry for the vice president has to be this: Are those constituencies truly for him, or is it simply that they have yet to focus on what Bradley offers?
It is to Gore's benefit to upset the current characterological dynamic, which favors Bradley, and refocus the race on issues.
To raise doubts among the college vote, Gore has attacked Bradley's call for near universal health care coverage as an extravagance the nation simply can't afford.
Now, that's a tricky argument for Gore, given that in 1993 and 1994 - when the government still had a serious deficit - he himself embraced universal coverage. (Gore's current, more modest plan would cover 3 million fewer people.)
But Bradley has given his rival an opening by offering a plan based on (sliding-scale) federal subsidies to allow poor and modest-income families to purchase health plans. More cost-effective approaches would be either a single-payer plan or a mandate requiring employers to insure their workers. But either would be certain to engender the sort of fierce business opposition that helped defeat President Clinton's plan in 1994.
Because Bradley's plan would subsidize many families that already have health care, it carries a hefty price tag.
Bradley's campaign pegs the cost at about $65 billion a year or $650 billion over 10 years; Gore argues, with some justification, that the actual cost would be much higher, at least $1.1 trillion over a decade.
That expense presents a target for Gore. In the Oct. 27 Dartmouth debate and since, he has offered a not-so-subtle class-based cost/benefit criticism.
If Bradley spends the entire surplus on health care, Gore warns, there will be no money left for other programs, such as saving Medicare or improving education.
''The numbers have to add up,'' Gore warned when he and Bradley debated. ''Spending more than the entire surplus and then piling on top of that proposals that may sound great but for which there is no money is something that ought to be looked at very carefully.''
More recently, Gore has tried to reinforce his black and Latino support, which might be attracted to Bradley's antipoverty proposal and his focus on racial harmony, by attacking Bradley's plan to replace Medicaid with a subsidy that would let poor families buy private health-care plans.
In an attack reminiscent of the fear-mongering ''Medi-scare'' campaign Clinton ran in 1996, Gore has accused his rival of trying to ''tear down'' Medicaid in a way that would leave minorities ''out in the cold.'' In Boston on Thursday, Gore continued his attack, saying Bradley's plan could spell disaster for those who depend on Medicaid.
So what will happen on the collision front?
Neither side knows - and each is nervous.
''Bradley's health care plan wipes out a hard-won surplus in one fell swoop,'' says Doug Hattaway, Gore's New Hampshire press secretary. ''That does not paint a pretty picture for Tsongas deficit hawks.''
But Bradley's camp thinks it will prove easier for their man to snaffle Gore's less affluent voters with the enticement of big new benefits than for Gore to make inroads into Bradley's college-educated crowd, who probably have a fairly clear take on Gore already.
''As they tune into the campaign, they will see a candidate who has an agenda of big solutions that speak directly to their interests,'' says Eric Hauser, a Bradley spokesman.
Who will prevail? It depends in large part on how effectively each candidate makes his argument. Which is why it's worth noting that so far, Gore has done a better job raising doubts about Bradley's program than Bradley has in assuaging them.
But with more than two months left till New Hampshire's Feb. 1 primary, one thing is certain: By the time voters cast their ballots, they will have been given plenty of reasons to rethink their original preference - no matter who that was.
