WASHINGTON — The Republican drive to overhaul financial regulations on Wednesday turned into a contentious debate over Democratic efforts to cast a spotlight on President Donald Trump's business empire and his refusal to release his tax returns.

House Republicans are working to undo much of the 2010 Dodd-Frank law that put the stiffest restrictions on banks and Wall Street since the 1930s Depression. Democrats don't have the numbers to stop their efforts in the House, but they are intent on making them pay a price if any conflicts of interest emerge for Trump down the road.

A House panel spent much of the day Wednesday debating an amendment that would bar the GOP replacement for the law from going into effect until the Office of Government Ethics certifies that the changes in the bill would not directly benefit Trump or any of his appointees with influence over federal regulations.

"As members of Congress develop a public policy, you have a responsibility to ensure this president is not benefiting," said Rep. Maxine Waters, the top Democrat on the House Financial Services Committee. "Why hasn't he shown his tax returns? That would help us understand whether or not he's benefiting from any of our work."

Republicans called the amendment as "partisan as it gets."

"One thing after the next, I see my colleagues on the other side do everything in their power to undermine this president and it's wrong," said Rep. Lee Zeldin, R-N.Y.

Presidents are not subject to the conflict-of-interest laws that their own appointees must follow, but until now they have followed them anyway to set an example. Trump is blazing a different trail by refusing to give up a financial interest in his company while turning over the reins to his adult sons and a senior executive.

Some ethics experts have called for Trump to sell off his assets and place his investments in a blind trust, an entity that his family would not control. That's what previous presidents have done.

On the second day of its contentious, marathon session, the GOP-led Financial Services Committee also rebuffed Democratic attempts to protect the Consumer Financial Protection Bureau, the five-year-old agency which enforces consumer protection laws and scrutinizes the practices of virtually any business selling financial products and services. That ranges from credit card companies to mortgage servicers to auto lenders.

Democrats said that when they created Dodd-Frank, they wanted to make the consumer agency as independent from political influence as possible.

Republicans complained that Congress has too little say over how the bureau operates.

"It's about checks and balances," said Rep. Jeb Hensarling, R-Texas, the chairman of the Financial Services Committee. "This is part of what we do."

Democrats also tried to preserve a new federal rule targeting consumers' retirement investments and the advice they receive from financial professionals. The Republican overhaul bill would repeal a Labor Department rule requiring brokers who recommend investments for retirement savers to meet the stricter standard that applies to registered advisers: They must act as "fiduciaries" — trustees who are obliged to put their clients' best interests above all.

Republicans on the panel said the rule, which hasn't yet taken effect, would strip individual investors of choices for their retirement savings.

Another Democratic attempt would block a provision in the Republican bill that would tighten congressional oversight of the Federal Reserve and crimp its emergency lending authority. The central bank and its approach to interest-rate policy have long been a target of criticism by conservative Republicans.

Republicans are likely to pass the measure in the House. But the bill faces significant obstacles in the Senate, where leaders have emphasized their desire to find areas of agreement to enhance economic growth. Democratic lawmakers predicted that at the end of the process, the bill would not become law despite an ally in the White House — Trump.

Soon after taking office, Trump ordered the Labor Department to delay implementing the fiduciary rule. The delay gave the administration a chance to rethink the rule and to revise or eliminate it.

The rule is intended to prevent investment professionals from steering clients toward high-commission investments that might not be in the clients' best interests.

Rep. Blaine Luetkemeyer, R-Mo., said the fiduciary rule is a slap in the face to the integrity of investment advisers. "If they don't give good advice, they're not going to be in business very long," he said.

The panel will continue working through the proposed replacement bill for the Dodd-Frank law on Wednesday and possibly into Thursday.