He didn't.
https://calmatters.org/politics/2019/04/trump-tax-california-salt-deduction-property-april/
For communications professor Jason Jarvis and his wife, Jun, California just got more expensive. The Inglewood couple, who last year paid $16,000 in state and local taxes, were only able to deduct $10,000 of it from their federal taxes this year.
The federal Tax Cuts and Jobs Act—signed last year by President Donald Trump and cheered by Republicans in Congress—cost the Jarvis family between $4,500 and $5,000 in deductions, raising their bill from the Internal Revenue Service even after a larger child tax credit for their 15-month-old son, Kellar.
https://smartasset.com/taxes/trumps-plan-to-eliminate-the-state-and-local-tax-deduction-explained
The state and local tax (SALT) deduction allows taxpayers of high-tax states to deduct local tax payments on their federal tax returns. The tax plan signed by President Trump in 2017, called the Tax Cuts and Jobs Act, instituted a cap on the SALT deduction. Starting with the 2018 tax year, the maximum SALT deduction available was $10,000. Previously, there was no limit. We take a closer look at what the reduced deduction has meant for residents of high-tax states like California, New York and New Jersey. If you’re concerned about the impact of these changes, consider working with a financial advisor to manage the impact of taxes on your financial plan.