The EV "mandate" was a Biden goal that EVs make up half of new cars sold by 2030.
The EV $7,500 tax credit "incentive" was signed int law in 2008 (Bush). It was modified in 2010 to phase out after a carmaker sold over 200,000 qualified EVs. It was further modified in 2023
https://www.irs.gov/credits-deductions/credits-for-new-clean-vehicles-purchased-in-2023-or-after