WASHINGTON - Sixteen Democratic senators called on President Bush to remove Kenneth Y. Tomlinson as head of the Corporation for Public Broadcasting because of their concerns that he is injecting partisan politics into public radio and television.
"We urge you to immediately replace Mr. Tomlinson with an executive who takes his or her responsibility to the public television system seriously, not one who so seriously undermines the credibility and mission of public television," wrote the senators.
They included Charles E. Schumer of New York, Joseph I. Lieberman of Connecticut, Jon Corzine and Frank R. Lautenberg of New Jersey, Bill Nelson of Florida, Edward M. Kennedy of Massachusetts and Dianne Feinstein and Barbara Boxer of California.
Also on Tuesday, Democratic lawmakers joined other supporters of public broadcasting, including children and characters from PBS children's programs, to protest House Republicans' proposed cuts in financing for the corporation.
The Democrats' letter follows a series of disclosures about Mr. Tomlinson that are now under investigation by the corporation's inspector general, including his decision to hire a researcher to monitor the political leanings of guests on the public policy program "Now," the use of a White House official to set up an ombudsman's office to scrutinize public radio and television programs for political balance, and payments approved by Mr. Tomlinson to two Republican lobbyists last year.
Mr. Tomlinson said he would not resign.
"There is no reason for me to step down from the chairmanship of the Corporation for Public Broadcasting," he said. "I am confident that the inspector general's report will conclude that all of my actions were taken in accordance with the relevant rules and regulations and the traditions of CPB."
The White House said Mr. Bush continued to support Mr. Tomlinson.
"Mr. Tomlinson was first nominated to the board by the past administration and was renominated in 2003," said Erin Healy, a White House spokeswoman. "He is the chair of an independent bipartisan board, and the president stands by the chairman."
A new problem emerged for Mr. Tomlinson on Tuesday, when evidence surfaced that he might have provided incorrect information about the hiring of a researcher last year to monitor political leanings of the guests of the "Now" program.
In a letter to Senator Byron L. Dorgan, Democrat of North Dakota, on May 24, Mr. Tomlinson said he saw no need to consult with the board about the contract with the researcher, Fred Mann, because it was "approved and signed by then CPB President, Kathleen Cox." But a copy of the contract provided by a person unhappy with Mr. Tomlinson's leadership shows that Mr. Tomlinson signed it on Feb. 3, 2004, five months before Ms. Cox became president. Ms. Cox stepped down in April after the board did not renew her contract.
Mr. Mann, who was paid $14,170 for his work by the taxpayer-financed corporation, rated the guests on the show by such labels as "anti-Bush" or "anti-DeLay," a reference to Representative Tom DeLay of Texas, the House majority leader. He classified Senator Chuck Hagel of Nebraska as a "liberal," even though Mr. Hagel is well-known as a mainstream conservative Republican.
Asked about the apparent discrepancy between the contract he signed and what he wrote to Mr. Dorgan, Mr. Tomlinson declined through a spokesman to comment.
Mr. Dorgan was sharply critical of Mr. Tomlinson.
"If he signed the contract, he was not telling the truth, which would be very troubling," Mr. Dorgan said on Tuesday. "He's trying to pawn some responsibility for this on others, which is very troubling. This guy has some real credibility problems."
At its first public meeting since the inquiry began, the corporation's board on Tuesday did not address who should be the organization's next president.
Mr. Tomlinson had made it clear in recent weeks that his top choice is Patricia Harrison, an assistant secretary of state and former co-chairwoman of the Republican National Committee. Public broadcasting executives say the choice is another instance of injecting politics into an organization that is supposed to be a political buffer. Mr. Tomlinson has told at least one lawmaker that Ms. Harrison would be a smart choice because of her credibility at the White House and on Capitol Hill.
Mr. Tomlinson began the meeting by calling for a bipartisan approach to public broadcasting: "When people with partisan positions come to the Corporation for Public Broadcasting, they leave their partisan positions at the door."
The other Democratic senators who signed the letter were Joseph R. Biden Jr. of Delaware; Maria Cantwell of Washington; Richard J. Durbin of Illinois; Tom Harkin of Iowa; Patrick J. Leahy of Vermont; Barbara A. Mikulski of Maryland; Debbie Stabenow of Michigan; and Ron Wyden of Oregon.