The answer matters in the University of Madison in Wisconsin, traditionally a centre of radicalism, and to the youthful six million audience of Rockline, a television and radio show broadcast from the campus and on which the Democratic candidates appeared last week.
As the question was asked, Mr Clinton and his running mate, Mr Gore, almost visibly flinched. At Madison, students take a dim view of the activities of Columbus, and the local Democratic Congressional candidate is a native American. But too categorical a condemnation of the great discoverer could be seized upon by President Bush as evidence of the Democrats' lack of patriotism.
Mr Gore evaded the question by producing a masterpiece of waffle. 'It is important to view the full record in the light of the full context and the full history of the age of discovery,' he said. And to laughter from assembled correspondents, Mr Clinton added: 'I basically feel the same way. Still, it was a remarkable achievement and it changed the whole world's view of geography and the possibility of life on this continent, and that's one reason many of us are here.'
With a 17-point lead over President Bush four weeks from the election, the priority of the Clinton campaign is to avoid making fresh enemies or giving Mr Bush a target to attack.
Earlier, in Milwaukee, Mr Clinton had appeared in his presidential mode, addressing a well-heeled local audience on foreign policy and denouncing Mr Bush for seeming to support 'stability at the expense of freedom'. But the attack was well-mannered. There was even a little bow to the President for building the alliance which won the Gulf war.
The problem for the Clinton campaign is that the Democrats would like the election to be tomorrow. They do not want to break any new ground. Paul Begala, a senior strategist who invariably accompanies Mr Clinton on the campaign trail, says the key to victory for the Democrats is to stick to the economic and social issues that gave Mr Clinton the nomination and his present lead. 'Whenever we've swerved from that we've lost ground,' Mr Begala says. He believes the reason that 'Bush's support dropped like a rocket' in the summer was because he repeatedly changed his tactics to cope with the challenge from Ross Perot, alternatively denouncing and embracing the Texas billionaire.
Over the next four weeks, Mr Clinton will stick to his moderate populism, hoping Mr Perot will self-destruct and Mr Bush will fail to persuade voters that the Democrats will raise taxes.
As the Clinton campaign swept through Wisconsin, then turned south to the key states of Ohio and Michigan last week, his advisers were putting a brave face on a series of minor setbacks. Dee Dee Meyers, Clinton's press spokeswoman, was saying, within minutes of Perot re-entering the race, that Perot no longer represented a mass movement. The Clinton staff was buoyed up by a CNN/
USA Today poll of which they had advance notice. It showed Mr Clinton with 52 per cent, Mr Bush 35, and Mr Perot 7. 'Look at the way his negative ratings have gone from 20 per cent when he dropped out to 66 per cent,' said Meyers.
Mr Perot may hurt Bush more than Clinton by taking away Republican votes in Texas while Mr Clinton's lead in California is big enough to withstand defections. But, at this stage in the campaign, the Clinton staff do not want any muddying of the waters, while, for Bush, almost any change is for the better. Mr Clinton was wrong-footed by Bush's abrupt change of tack on the debates, suddenly offering four of them after being punished by the Democrats for an earlier refusal to debate. Democratic headquarters at Little Rock, in Arkansas, was slow to end its ploy of dispatching a supporter dressed up as a chicken to Bush rallies.
The announcement of the debates and the reappearance of Mr Perot limited Mr Clinton's exposure on the network news, but he remains a tireless campaigner. During a visit to a pre-school centre outside Milwaukee, he was told by five-year-old Adam Rittle: 'We've got a fort in the woods. Want to see it?' Candidate, Secret Service, cameramen and journalists clambered up a hillside, stooping under low branches, until they could view the small den the boy had constructed out of brushwood.
Mr Clinton himself looks a little worn in the morning, his voice often hoarse, but he improves towards evening - which is a slight political disadvantage, since this is too late for the main television network news programmes. He looks at ease as his audience changes from foreign policy academics in Milwaukee to tough-looking Teamsters in Toledo. 'Overall, he is a more professional politician than any Democratic leader since LBJ,' said a specialist in Ohio politics.
Even when the national networks are devoted to other topics, Mr Clinton spends hours being interviewed by local television stations, a technique pioneered by George Bush in the 1988 presidential campaign. The advantage is that remarks are run in full and the local anchormen often ask 'softball' questions. On Friday, an anchor on a television station in New Mexico, interviewing Mr Clinton by satellite, asked him what, on being elected, 'good news will you bring to the Land of Enchantment?', as New Mexico likes to be known.
All this annoys the national media, packed into two buses behind the Clinton party. He has not given a general news conference in two weeks. This is partly to avoid questions on the draft, but most of all because the campaign does not want to answer questions about its basic economic message that 'two-thirds of Americans work harder for less money than 10 years ago'. This is endlessly repeated at meetings and is always at the core of Mr Clinton's appeal, though emphasis on other themes changes with the audience. To students in Madison, there is a commitment to choice on abortion, while in industrial Toledo, home of the Jeep, the emphasis is on economic and social issues. At a breakfast meeting with eight unemployed people at Bud and Luke's restaurant in Toledo, which looks like Sheffield, Clinton sounded well informed without being patronising or stagey, despite the presence of 15 television cameras. Outside in the street he was greeted by a Vietnam veteran, who said he did not like Mr Clinton's draft record, but added: 'The reason I'm going to vote for you is that when you wake in the morning, you don't look at the Wall Street Journal to see how your stocks are doing.'
The previous weekend, President Bush had taken a train through Toledo without stopping, much to the rage of Toledans. Mr Clinton mentioned the snub frequently. 'He didn't stop here, but on 3 November you can stop him permanently,' he told a rally outside Bud and Luke's. The last unemployment figures before the election had just been announced, showing that 9.5 million Americans are unemployed: a marginal drop, but of little use to Mr Bush, because some people had simply given up looking for work.
One Democratic politician said last week that Mr Clinton is home and dry 'unless it is discovered that he shot his mother'. Others are more cautious. Although Mr Clinton is quick thinking, he did not do well in the debates during the Democratic primaries, boring people by lecturing them. At his meetings this week, he often talked for about 10 minutes too long, well past the point that his audience had begun to shuffle their feet. All three candidates are distrusted by so many voters that a small slip could have a disproportionate impact. Mr Clinton must be careful - even about Christopher Columbus.