On taxes, deficits and prices, Trump, Biden and Harris all seem determined to trash as many economic principles as possible.

these ideas look politically shrewd. But if implemented, they may come back to haunt a future president who learns just how harmful or impractical they are. No taxes on tips Tax policy usually involves a trade-off between equity (treating people fairly) and efficiency (improving growth and consumer well-being). Former President Trump’s proposal to end taxes on tips, quickly adopted by Harris, manages to be both inequitable and inefficient. It’s inequitable because it would tax people paid mostly via wages, such as cooks, more heavily than similar people paid mostly via tips, such as waiters. It’s inefficient because it rewards a clumsy and often arbitrary form of compensation. Research finds tips only loosely correlated with quality of service. Tips survive because of social norms and psychological bias: restaurants that replace tips with higher wages have to raise prices, but customers prefer lower posted prices even when the all-in expense is the same.

Price and rent controls The U.S. hasn’t had economywide wage and price controls since the early 1970s, and Harris isn’t proposing them now. She and Biden are proposing something narrower: taking federal tax benefits away from corporate landlords that raise rents more than 5%, and cracking down on “price-gouging.” In spirit, these are similar to existing federal, state and local laws that regulate prices of insurance and drugs or during natural disasters. Yet as with formal price controls, they short-circuit the essential role of higher prices: drawing in new supply and encouraging substitution toward cheaper alternatives. Price controls are justified when a few companies enjoy market power, because they are monopolists or oligopolists, or because of an emergency. Those conditions don’t apply to apartments or food.

Tariffs Economists have a visceral dislike of tariffs. They’re a tax on imports, and imports are quite useful. In recent years, a more nuanced view has emerged. Trump’s tariffs on China, which Biden continued and Trump now proposes to expand, reduce U.S. vulnerability to a geopolitical adversary. But Trump’s proposed 10%, or even 20%, “baseline” tariff on every country and product serves no obvious purpose. He claims this will cause American consumers to buy U.S. instead of foreign-made goods, boosting jobs and reducing the trade deficit. Perhaps Trump thinks tariffs give him leverage to force other countries to reduce trade barriers. Some might, but others, such as the European Union and China, will likely retaliate, as they did in his first term. In a May report, Deutsche Bank economists show that manufacturing employment deteriorated in the U.S. after Trump’s trade war began in 2018, with the biggest impact in the most manufacturing-intensive counties. The Tax Foundation estimates Trump’s 10% tariff would shrink U.S. output by 0.7% and cost 505,000 jobs.

The tax giveaway arms race Harris has proposed a $6,000 tax credit for the parents of a newborn child. Not to be outbid, Trump’s running mate JD Vance has pitched a $5,000 credit for every child, no matter how rich the parents. The fiscal arms race doesn’t stop there; Harris is promising a $25,000 tax credit for first-time home buyers. Trump would end income taxes on Social Security benefits. These ideas aren’t inherently bad, but boy, they’re expensive. The Committee for a Responsible Federal Budget estimates Harris’s promises, beyond those already made by Biden, cost about $1 trillion over a decade; Trump’s Social Security tax repeal would cost at least $1.6 trillion.

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