A new report shows that U.S. Rep. Greg Walden (R-Hood River) represents the congressional district that by one measure has benefited more from the Affordable Care Act than any other led by a Republican and more than all but three Democratic districts.

As President Donald Trump and the Republican-controlled Congress grapple with the realities of their pledge to "repeal and replace" the ACA, nobody will play a bigger role than Walden.

He is the new chairman of the House Committee on Energy and Commerce, which is where Republicans will begin their work on the law also known as Obamacare.

Last month, after the House passed its 2017 budget resolution, Walden said he was ready to start that work.

"Today's vote allows House committees to get to work on repealing Obamacare and rebuilding our health care system," Walden said in a Jan. 13 statement. "Put simply, Obamacare is a mess. We're ready to begin advancing solutions that will help families, lower costs, and restore fairness in the relationship between patients and their doctors. Critical work lies ahead, and we are up to the task of delivering badly needed relief for patients."

But repeal could come at a major cost to Walden's constituents. Oregon has been one of the most aggressive adopters of Medicaid expansion, a key component of the ACA. That expansion provided health insurance to more than 400,000 low-income Oregonians, many of them Walden's constituents.

In fact, a new report of the consequences of repealing the ACA from the House Democrats highlights an extraordinary fact—Walden's district, which covers 20 Oregon counties and an area about the same size as New York, New Jersey and Connecticut combined, added more new Medicaid recipients under the ACA than any of the congressional districts in GOP control and all but three Democratic districts (New York's 7th, 13th and 15th districts).

Here are the numbers:

Walden's spokesman did not immediately provide answers to questions about the figures, but Walden spoke to Think Out Loud host Dave Miller on OPB Wednesday and the conversation touched on what Walden thinks may happen with Medicaid.

"Nothing we're going to do is going to pull the rug out from under people on Mediciad today," Walden told Miller. "If you are on it you stay on it. You continue to get that payment. Going forward, it's going to be more complicated."

Walden yesterday disputed critics—including US Rep. Kurt Schrader (D-Ore.)—who accused Republicans of keeping their rushed replacement bill a secret from other members of Congress and the public. "So who exactly gets to see the bill that's going to take healthcare away from 400,000 Oregonians? #NoOneGetsACopy," Schrader tweeted Thursday.

U.S. Sen. Rand Paul (R-Ky.) meanwhile claimed "the House Obamacare bill is under lock & key, in a secure location, & not available for me or the public to view."

Walden's office responded to critics with a statement:

Reports that the Energy and Commerce Committee is doing anything other the regular process of keeping its members up to speed on latest developments in its jurisdictions are false. We are continuing to work on drafting and refining legislative language to provide relief from a failing law. Part of that process is giving committee members and staff the opportunity to work closely together to draft a bill that reflects the concerns of our constituents and reflects our mandate from voters to repeal and replace Obamacare. Simply put, Energy and Commerce majority members and staff are continuing to discuss and refine draft legislative language on issues under our committee’s jurisdiction.

WW staff reporter Corey Pein contributed reporting.