In refusing to release his tax returns, President Trump bucked decades of tradition and set off a Democrat hunt to obtain them. Now several statehouses are looking at making their release a condition of the 2020 presidential election: Show us your tax returns, or you can’t be on the ballot.

Eighteen states have considered legislation this year that would require presidential and vice presidential candidates to post their tax returns to appear on the ballot during a primary or general election, according to data from the National Conference of State Legislatures (NCSL).

Proponents of the bills, such as the one passed by the Washington state Senate this week, say they are aimed at increasing transparency and returning to the “norm” of candidates releasing their financial records. But Democratic lawmakers behind the some of the legislation have admitted they are also very much about Trump, which raises legal and political questions about how far states can — or should — go in regulating who appears on their ballot, especially in a hyperpartisan climate.