Cailin R. Slattery (UC-Berkeley; Google Scholar), Alisa Tazhitdinova (UC-Santa Barbara; Google Scholar) & Sarah Robinson (UC-Santa Barbara; Google Scholar), Corporate Political Spending and State Tax Policy: Evidence from Citizens United (NBER 30352) (Aug. 2022):

To what extent is U.S. state tax policy affected by corporate political contributions? The 2010 Supreme Court Citizens United v. Federal Election Commission ruling provides an exogenous shock to corporate campaign spending, allowing corporations to spend on elections in 23 states which previously had spending bans.

Ten years after the ruling and for a wide range of outcomes, we are not able to identify economically or statistically significant effects of corporate independent expenditures on state tax policy, including tax rates, discretionary tax breaks, and tax revenues.

Wall Street Journal Editorial, Citizens United Bought . . . Nothing?:

Corporate dollars made zero difference in state tax policy, a study says.

According to progressive demonology, the Supreme Court’s 2010 ruling in Citizens United v. FEC unleashed corporate election spending, allowed fat cats to buy politicians, and turned the U.S. into an oligarchy, more or less. This is a canard, and further proof is a new study that sifts data to see if Citizens United had any effect on state tax policy.

The answer is no. … If billionaires were able to buy elections to lower state taxes, you’d think they would have done it by now. …

This kind of evidence is persuasive because tax policy affects the bottom line, so companies really care about it and they generally pull in the same direction.