The author wants to prevent a race to the bottom on taxes. A race to the bottom would be bad if taxes are fair or already too low. But if taxes were too high, a

The author wants to prevent a race to the bottom on taxes. A race to the bottom would be bad if taxes are fair or already too low. But if taxes were too high, a race to the bottom (or just the threat of one) would be a good thing, as it could keep unreasonable tax rates in check. To put it differently: if companies and individual workers were not able to shop around for the tax regimes they prefer, what would prevent cities and states from raising taxes to unreasonably high levels? Taxes are kept in check by the threat of companies and high-earning taxpayers moving somewhere else. I would rather live world where taxation is subject to a race to the bottom than in a world where nothing prevents unfairly high tax rates. The latter is definitely worse.