Sens. Ron Wyden (D-Ore.) and Chris Murphy (D-Conn.) on Thursday renewed efforts that would require presidential candidates to release their tax returns.

In a conference call Thursday with reporters, Wyden, the top Democrat on the Finance Committee, said that when lawmakers return to the Capitol next month he will urge them to take up legislation he introduced on May 25 that would require all presidential nominees of major parties to release their last three years of tax returns within 15 days of accepting their party’s nomination.

If the nominee fails to do so, the Federal Election Commission would request the returns from the Treasury Department and then make them public. The bill would take effect immediately if signed into law by President Obama.

“You just don’t get to hide your tax returns from public view when you are running for president of the United States,” Wyden told reporters.

He noted that nominees for executive branch positions lower than the presidency are required to give their tax returns to Senate committees for review, and he questioned Trump’s reasoning for not releasing his returns. Trump has said he is undergoing an Internal Revenue Service audit and that he will release the returns after the audit is complete.

“An ongoing audit is just not an excuse to hide your returns,” Wyden said. “In fact, nobody’s 2015 returns would be under audit this soon. So if Mr. Trump filed on time, the most recent excuse we’ve heard simply doesn’t hold up.”

Wyden’s bill —which has five co-sponsors, including Sen. Elizabeth Warren (D-Mass.) and Sen. Tim Kaine (D-Va.), Hillary Clinton’s running mate — has languished in the Committee on Rules and Administration for almost three months.

Senate Majority Leader Mitch McConnell (R-Ky.) weighed in on the tax-return issue around the same time Wyden introduced his bill.

“For the last 30 or 40 years, every candidate for president has released their tax returns, and I think Donald Trump should as well,” McConnell told Business Insider on May 31.

In today’s conference call, Murphy, a member of the Senate Foreign Relations Committee, also called for scrutiny of Trump’s foreign investments.

“It’s really important for the American public to know whether Donald Trump has investments in Russia, and we probably know the answer to that already — that he does,” Murphy said, adding that Trump has released his taxes in the past, “when it would have served to his advantage.”