By LISA MASCARO, AP Congressional Correspondent

WASHINGTON (AP) — Republicans have suffered a sizable setback on one key aspect of President Donald Trump’s big bill after their plans to gut the Consumer Finance Protection Bureau and other provisions from the Senate Banking Committee ran into procedural violations with the Senate parliamentarian.

Republicans in the Senate proposed zeroing-out funding for the CFPB, the landmark agency set up in the aftermath of the 2008 financial crisis, to save $6.4 billion. The bureau had been designed as a way to better protect Americans from financial fraud, but has been opposed by many GOP lawmakers since its inception. The Trump administration has targeted the CFPB as an example of government over-regulation and overreach.

The findings by the Senate parliamentarian’s office, which is working overtime scrubbing Trump’s overall bill to ensure it aligns with the chamber’s strict “Byrd Rule” processes, signal a tough road ahead. The most daunting questions are still to come, as GOP leadership rushes to muscle Trump’s signature package to floor for votes by his Fourth of July deadline.

Sen. Tim Scott, R-S.C., the chairman of the Banking Committee that drafted the provisions in question, said in a statement, “My colleagues and I remain committed to cutting wasteful spending at the CFPB and will continue working with the Senate parliamentarian on the Committee’s provisions.”

For Democrats, who have been fighting Trump’s 1,000-page package at every step, the parliamentarian’s advisory amounted to a significant win.

“Democrats fought back, and we will keep fighting back against this ugly bill,” said Sen. Elizabeth Warren of Massachusetts, the top Democrat on the Banking Committee, who engineered the creation of the CFPB before she was elected to Congress.

Warren said that GOP proposals “are a reckless, dangerous attack on consumers and would lead to more Americans being tricked and trapped by giant financial institutions and put the stability of our entire financial system at risk–all to hand out tax breaks to billionaires.”

The parliamentarian’s rulings, while advisory, are rarely, if ever ignored.

With the majority in Congress, Republicans have been drafting a sweeping package that extends some $4.5 trillion tax cuts Trump approved during his first term, in 2017, that otherwise expire at the end of the year. It adds $350 billion to national security, including billions for Trump’s mass deportation agenda. And it slashes some $1 trillion from Medicaid, food stamps and other government programs.

All told, the package is estimated to add at least $2.4 trillion to the nation’s deficits over the decade, and leave 10.9 million more people without health care coverage, according to the nonpartisan Congressional Budget Office’s review of the House-passed package, which is now undergoing revisions in the Senate.

The parliamentarian’s office is responsible for determining if the package adheres to the Byrd Rule, named after the late Sen. Robert Byrd of West Virginia, who was considered one of the masters of Senate procedure. The rule essentially bars policy matters from being addressed in the budget reconciliation process.

Senate GOP leaders are using the budget reconciliation process, which is increasingly how big bills move through the Congress, because it allows passage on a simple majority vote, rather than face a filibuster with the higher 60-vote threshold.

But if any of the bill’s provisions violate the Byrd Rule, that means they can be challenged at the tougher 60-vote threshold, which is a tall order in the 53-47 Senate. Leaders are often forced to strip those proposals from the package, even though doing so risks losing support from lawmakers who championed those provisions.

One of the biggest questions ahead for the parliamentarian will be over the Senate GOP’s proposal to use “current policy” as opposed to “current law” to determine the baseline budget and whether the overall package adds significantly to deficits.

Already the Senate parliamentarian’s office has waded through several titles of Trump’s big bill, including those from the Senate Armed Services Committee and Senate Energy & Public Works Committee.

The Banking panel offered a modest bill, just eight pages, and much of it was deemed out of compliance.

The parliamentarian found that in addition to gutting the CFPB, other provisions aimed at rolling back entities put in place after the 2008 financial crisis would violate the Byrd Rule. Those include a GOP provision to limit the Financial Research Fund, which was set up to conduct analysis, saving nearly $300 million; and another to shift the Public Company Accounting Oversight Board, which conducts oversight of accounting firms, to the Securities and Exchange Commission and terminate positions, saving $773 million.

The GOP plan to change the pay schedule for employees at the Federal Reserve, saving $1.4 billion, was also determined to be in violation of the Byrd Rule.

The parliamentarian’s office also raised Byrd Rule violations over GOP proposals to repeal certain aspects of the Inflation Reduction Act, including on emission standards for some model year 2027 light-duty and medium-duty vehicles.

Associated Press writer Mary Clare Jalonick contributed to this report.