“I’d like to be a resource to my former colleagues, to the extent that I can, to the administration, to the stakeholders and to people interested in just kind of knowing how this is all going to play out,” he said. “I am most comfortable with the word resource.”

Image Tom Daschle, President Obamas first pick for health secretary and reform czar, with the president-elect in Chicago in December. Credit... Charles Dharapak/Associated Press

White House officials say they appreciate his help. “He is one of a number of people that provides outside advice to the White House, and the president greatly appreciates that advice and Tom’s friendship,” said Dan Pfeiffer, a spokesman for the White House who previously worked for Mr. Daschle. Mr. Pfeiffer added that the former senator was “a recognized expert on health reform who knows more about the legislative process than just about anyone.”

Critics, though, say his ex officio role gives Alston & Bird’s health care clients privileged insights into the policy process. They say Mr. Daschle’s multiple advisory roles illustrate the kind of coziness with the lobbying world that Mr. Obama vowed to end. If he had been confirmed as health secretary, Mr. Daschle would have been subject to strict transparency and ethics rules.

His position, some liberals say, raises at least an appearance of a conflict of interest. “I hope the president can make a decision based on what the country wants, not what a handful of Daschle’s clients want,” said Representative Lynn Woolsey of California, a leader of the progressive caucus.

Clients of Alston & Bird say Mr. Daschle advises them, sometimes indirectly through the firm’s registered lobbyists, about the personalities of his former colleagues, as well as strategies to achieve their policy goals.

“He would tell us, ‘Make sure you present the value proposition of home care with as great detail as you can, so Congress understands that home care is part of the solution rather than a cost to be cut,’ ” said William A. Dombi, a lawyer at the National Association for Home Care and Hospice.

Some of the health overhaul bills would make deep cuts in Medicare payments for home health services, but Mr. Daschle has instead argued for an increase. And though he does not lobby, he took that message to Capitol Hill last month, giving a paid speech at a meeting for Congressional staff convened by a group of home health care equipment concerns.