Rather than going all out to demonstrate Donald Trump's unfitness, Hillary Clinton should use the first Presidential debate to lay out her own motivations and policy goals. PHOTOGRAPH BY JOHN LOCHER / AP

If the late philosopher Isaiah Berlin were alive to watch Monday night’s Presidential debate, he would surely recognize the ways in which the two candidates on the stage personify his famous metaphor of hedgehogs and foxes. In Berlin’s terms, Donald Trump is a classic hedgehog. He knows, or claims to know, one big thing: the United States and the world are going to hell in a handbasket, and they need a strong man like him to fix things. Hillary Clinton, by contrast, is one of Berlin’s foxes. She knows many things.

“Stronger Together,” the policy book that Clinton and her running mate Tim Kaine recently published, runs to almost three hundred pages, and contains chapters on everything from clean energy to the financial burdens facing family caregivers, to cybersecurity. One of Clinton’s challenges during her campaign has been how to capture her multi-pronged platform in a short, catchy message. The most memorable slogan her campaign has come up with—“I’m With Her”—evokes her gender rather than her ideas.

If you accept the hedgehog-and-fox taxonomy (and even Berlin readily admitted that it shouldn't be taken too literally), the circumstances going into Monday night might appear to favor Trump. Television, it is often said, is a visual medium that doesn’t lend itself easily to extended policy discussions. Modern Presidential debates are often viewed as gladiatorial contests, in which the aim is to wound your opponent while seeking to avoid suffering a deadly laceration of your own. Trump is a reality-television star, and, as he demonstrated in the Republican debates, he can wield a bludgeon.

If some of the reports about the candidates’ debate prep are accurate, Clinton is nonetheless preparing to engage in psychological warfare. The New York Times reported on Saturday that “Mrs. Clinton has concluded that catching Mr. Trump in a lie during the debate is not enough to beat him. She needs the huge television audience to see him as temperamentally unfit for the presidency, and that she has the power to unhinge him.”

It is to be hoped that these reports are inaccurate. Of course, Clinton should call out Trump whenever he demonstrates his inability to stick to the truth. And if the opportunity arises she should needle him about some of his glaring vulnerabilities, such as the scandals surrounding Trump University and Trump’s charitable foundation. But betting everything on having Trump come unglued would be an error, because it would put the onus on him. Merely by maintaining his composure and avoiding a blowup, he could frustrate the Clinton campaign's designs.

Surely, Clinton would be better served by playing to her strengths, which are considerable. As she demonstrated while running against Barack Obama in 2007 and 2008, and again during this year’s Democratic primaries, she is a strong debater, who combines an impressive command of the issues with an ability to think on her feet. Rather than going all out to demonstrate Trump’s unfitness to be President, which the polls indicate is already evident to a majority of the electorate, her main aim at Monday’s debate should be to lay out her own motivations and policy goals. In recent months, both of these things have been overshadowed, partly by the scandal surrounding her e-mails and partly by Trump’s big simplistic slogans: build a wall, keep out Muslims, get tough on China, and so on.

As it happens, Clinton’s agenda, as my colleague Adam Davidson also wrote the other day, does have a unifying theme. It’s the same one that Democrats have been running on for twenty-five years, a period in which they have won the popular vote in five out of six Presidential elections, and it involves using the power of the government to tilt the economy in favor of working people. Trump, although he talks like a populist, has largely adopted the regressive economic policies of the Republican establishment. Here are some examples of the two candidates’ policy differences:

Clinton would raise the federal minimum wage to twelve dollars, and she supports efforts to set a fifteen-dollar minimum wage for some areas of the country. Trump doesn’t believe in a federal minimum wage.

Clinton would raise taxes on high earners and use the money to pay for things like expanded preschool and free tuition at public colleges for the children of middle-class and lower-income families. Trump’s tax plan is a huge giveaway to the rich.

Clinton would use the tax system to encourage corporations to share their profits with their workers. Trump would slash the corporate tax rate to fifteen per cent without doing anything to encourage profit sharing.

Clinton would seek to expand the Affordable Care Act, bringing down the cost of co-payments and deductibles, doubling funding for low-cost community health centers, and establishing a public option to compete with private insurers. Trump would repeal the Affordable Care Act, and he hasn’t said what would replace it.