Why can’t New York release Mr. Trump’s state tax returns?

State laws generally prohibit such private tax information from being released. The bill would amend those laws.

Still, there are other issues at play.

Federal laws, for instance, shield federal tax information. If New York were to release federal return information contained within a state return, the I.R.S. wouldn’t be happy and could even “cease cooperation with the state,” said Daniel Hemel, an assistant professor at the University of Chicago Law School.

Remind me again: Why do Democrats want the tax returns?

Mr. Trump has kept many details of his personal and business finances a secret. He has never publicly released his tax returns, breaking decades of tradition among presidential candidates.

Several inquiries in New York and Washington — as well as a lengthy New York Times investigation — have questioned whether Mr. Trump skirted any laws in turning a collection of middle-class apartment buildings he inherited from his father into a global real estate empire.

What could Mr. Trump’s New York tax returns show?

Because New York has been Mr. Trump’s home state, and where his real estate empire has its headquarters, those returns could reveal much of the same financial information as a federal return.

How else have lawmakers tried to get Mr. Trump’s taxes?

The New York Truth Act, a bill introduced in the Legislature in 2017, would have required the Department of Taxation and Finance to release five years’ worth of income tax returns from eight officials if they earned income in New York: the president, vice president, New York’s two United States senators and four statewide elected officials, including the governor and the attorney general.

That bill now has enough support to pass the Legislature.

Another bill would require candidates for president and vice president to reveal their past tax returns in order to appear on primary and general election ballots.