(CNN) -- California will send legislation to Gov. Gavin Newsom's desk requiring presidential candidates to submit five years' worth of tax returns in order to appear on the ballot, joining 18 other states in a jab at President Donald Trump's refusal to release his tax returns.
California joins New York, Illinois and Washington, among other states, that have introduced bills requiring all candidates to release their individual tax returns to qualify for the presidential primary ballot. Tax returns have become a key 2020 issue, with Trump refusing to surrender them and Democratic presidential candidates sharing their tax information with varying degrees of timeliness.
The state's Senate passed the measure by a 27-10 party line vote Thursday, but whether Newsom, a Democrat, will sign the bill remains unclear.
Newsom spokesman Jesse Melgar told CNN, "with regard to this and all proposed legislation, should the bill reach the Governor's Desk it would be evaluated on its own merits."
While former California Gov. Jerry Brown vetoed similar legislation in 2017 , Newsom has shown support for tax returns in his own political career, releasing his tax returns as a candidate and promising to continue releasing them every year as governor.
Democratic California state Sens. Mike McGuire and Scott Wiener, who introduced the bill, were open about their efforts to hold Trump accountable with the legislation.
"The President's refusal to share his tax returns with the American people goes against longstanding transparency norms and undermines the trust between government and those it serves," Wiener wrote in a statement. "We deserve to know that the President is in fact acting for the good of the people and not in his own monetary self-interest."
McGuire added, "Voters deserve to know, for example, if the President is putting America's security at risk through his tangled web of business dealings with corporate interests and his dealings with foreign governments and foreign banks."
The president has faced increasing, multi-front scrutiny from congressional investigators, with Democrats taking the battle over subpoenas to Deutsche Bank and Capital One for Trump's past financial records to court last month. But the administration has fought back, with Treasury Secretary Steven Mnuchin ignoring House Democrats' April deadline for submitting Trump's tax returns in favor of his department taking "final action on the Committee's request by May 6."
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