Every former director of the nonpartisan Congressional Budget Office wrote to congressional leadership Friday with a simple message: step off.

The office, a frequent punching bag for Republicans amid their repeated failed efforts to repeal and replace Obamacare, came under additional scrutiny after a series of failures in the Senate to collect enough votes even to hold a vote on the repeal effort, at least for now.

“The undersigned represent every former Director of the Congressional Budget Office,” the former officials wrote. “We write to express our strong objection to recent attacks on the integrity and professionalism of the agency and on the agency’s role in the legislative process.”

Congressional Republicans have sent draft bill after draft bill to the CBO in recent weeks, though the resulting analyses have never shown Republicans’ desired results of expanded care and lower prices.

The office’s most recent estimate found that a slightly revised Senate repeal effort — even without an amendment from Sen. Ted Cruz (R-TX) to allow the sale of deregulated insurance plans — would result in 22 million more people without health coverage in 10 years, versus the status quo. On Wednesday, a CBO analysis found that a simple “repeal-and-delay” bill would result in 32 million more people without coverage over the next decade.

Republicans have, consistent with a months-long pattern, attempted to discredit the analyses.

House Speaker Paul Ryan (R-WI) called the 22 million number “bogus” on Thursday, asserting that many people would choose not to buy insurance without an Obamacare mandate incentivizing the purchase. However, the CBO estimated most coverage losses would come from cuts to Medicaid.

And Senate leadership turned to the Department of Health and Human Services — reportedly with the help of the consulting firm McKinsey — to score Cruz’s amendment. The analysis has been widely criticized.

Perhaps most notably, the official White House Twitter account reposted a video critical of the CBO, hammering home the theme “faulty numbers = faulty results.”

The CBO continues to prove its models simply can't be trusted to accurately predict the outcomes of important healthcare legislation. https://t.co/iNOxKaFomc — The White House (@WhiteHouse) July 20, 2017

The former CBO directors seemed to indirectly reference the video in their letter, writing that the office works “for the Congress, and only the Congress.”

“CBO began serving the Congress in 1975,” they wrote. “Over the past 42 years CBO has been firmly committed to providing nonpartisan and high-quality analysis — and that commitment remains as strong and effective today as it has been in the past. Because CBO works for the Congress, and only the Congress, the agency’s analysis addresses the unique needs of legislators.”

Read the former CBO directors’ full letter here, or below:

Dear Mr. Speaker, Madam Leader, Mr. Majority Leader, and Mr. Minority Leader: The undersigned represent every former Director of the Congressional Budget Office (CBO). We write to express our strong objection to recent attacks on the integrity and professionalism of the agency and on the agency’s role in the legislative process. CBO began serving the Congress in 1975. Over the past 42 years CBO has been firmly committed to providing nonpartisan and high-quality analysis — and that commitment remains as strong and effective today as it has been in the past. Because CBO works for the Congress, and only the Congress, the agency’s analysis addresses the unique needs of legislators. To meet the standard of nonpartisan objectivity, CBO makes no recommendations about policy, regularly consults with researchers and practitioners with a wide range of views (as can be seen in the agency’s panels of advisers and reviewers for major studies), and enhances its transparency by releasing extensive descriptions of its analytic techniques and forecast record. To produce estimates of high quality, CBO uses its detailed understanding of federal programs and economic conditions, ongoing interactions with government officials and private-sector experts, the best academic research, and the latest available data consistent with the timing of the Congressional budget process. CBO’s approach produces consistent comparisons of competing legislative proposals and unbiased projections of the impact of policy changes. Unfortunately, even nonpartisan and high-quality analysis cannot always generate accurate estimates. Policy changes are often complex, the economy is dynamic and defies precise prediction, and many policies are modified over time. However, such analysis does generate estimates that are more accurate, on average, than estimates or guesses by people who are not objective and not as well informed as CBO’s analysts. In sum, relying on CBO’s estimates in the legislative process has served the Congress — and the American people — very well during the past four decades. As the House and Senate consider potential policy changes this year and in the years ahead, we urge you to maintain and respect the Congress’s decades-long reliance on CBO’s estimates in developing and scoring bills. Sincerely, Dan L. Crippen

Former Executive Director, National Governors Association (CBO Director, 1999–2003) Douglas W. Elmendorf

Dean and Don K. Price Professor of Public Policy, Harvard Kennedy School (CBO Director, 2009–2015) Douglas Holtz-Eakin

President, American Action Forum (CBO Director, 2003–2005) June E. O’Neill

Wollman Distinguished Professor Of Economics, The City University of New York (CBO Director, 1995–1999) Peter R. Orszag

Vice Chairman of Investment Banking and Managing Director, Lazard (CBO Director, 2007–2008) Rudolph G. Penner

Institute Fellow, Urban Institute (CBO Director, 1983–1987) Robert D. Reischauer

Distinguished Institute Fellow and President Emeritus, Urban Institute (CBO Director, 1989–1995) Alice M. Rivlin

Senior Fellow, The Brookings Institution (CBO Director, 1975–1983)

Correction: An earlier version of this post said one CBO estimate found Republicans’ repeal bill would result in “32 million fewer people without coverage” in 10 years. The opposite is true.