Senators faced off Thursday over legislation relating to their opposing party’s presidential nominees on the Senate floor.

Some Senate Democrats made a last-ditch effort Thursday to pass a law requiring presidential candidates to release their tax returns. As a response, Republicans tried to pass a bill relating to handling classified information.

Oregon Democratic Sen. Ron Wyden attempted to pass the Presidential Tax Transparency Act, a bill aimed at GOP presidential nominee Donald Trump, who has so far refused to release his returns.

[Wyden, Murphy to Push Tax Legislation Aimed at Trump]

Senate Majority Whip John Cornyn of Texas blocked that effort, and asked to modify Wyden’s request to pass the bill to include passage of another measure relating to Democratic nominee Hillary Clinton’s use of a private email server when she was secretary of State.

That bill would prohibit or revoke security clearances for a federal employee who has “exercised extreme carelessness in the handling of classified information.” Wyden objected to that change and Cornyn objected to the Oregon Democrat’s original request to pass the tax return bill.

“Oh, how I wish it wasn’t necessary to have to pass legislation to ensure that there’s transparency, accountability and honesty in American elections,” Wyden told reporters after his floor action.

The senator was joined at the press conference by fellow Democrats, all pushing for the Senate to act on the tax return legislation. Wyden indicated that he may try to pass the bill again before the Senate leaves this month. 

[GOP Congressman to Trump: Release Your Tax Returns]

“Let me see. I’m going to be talking to more Republican colleagues. I’m going to be particularly looking for those who made statements that there ought to be disclosure and we’ll go from there,” he said. “But certainly, I’m going to do everything we can before we leave, working with colleagues to get this passed.”

Presidential candidates from both major parties have disclosed their tax returns since the 1970s. Democrats said the returns shed light on the candidates’ tax brackets, financial connections to foreign governments and special interests and charitable donations.

“A candidate who refuses to release his or her tax returns is hiding something,” said California Sen. Barbara Boxer. 

Andy Van Wye contributed to this report.Contact Bowman at bridgetbowman@rollcall.com and follow her on Twitter @bridgetbhc.