A magazine edited by a conservative writer who began work yesterday as President Bush’s top domestic policy adviser, Karl Zinsmeister, may have run afoul of fair-employment laws by taking out advertisements that sought “young” applicants.

Some of the ads for the American Enterprise magazine also listed as a contact a pseudonym belonging to a long-dead British writer who was an early champion of conservatism, Gilbert Chesterton.

“Seeking a skilled young graphic designer with a clean, elegant, uncluttered aesthetic to lay out and produce a thriving national monthly glossy,” said one such ad published last year on a Web site for writing and publishing professionals, Mediabistro.com.

“Youngish applicants especially welcome if you are a proven whiz kid,” another ad, for a managing editor position, said.

A law professor who has pursued several age discrimination cases in the capital, John Banzhaf, said District of Columbia law bars references to age in recruiting advertisements. “Generally, that would be illegal,” Mr. Banzhaf, a professor at George Washington University, told The New York Sun, after hearing the quotes from the ads. “I don’t think you can say that without violating the D.C. Human Rights Act.”

The ads state that the jobs in question would be located at the Washington headquarters of the conservative think tank that sponsors the magazine, the American Enterprise Institute.

Mr. Zinsmeister, 47, did not respond to an e-mail inquiring about the ads. A White House spokesman, Peter Watkins, referred questions about the ads to the American Enterprise Institute.

A spokeswoman for the think tank, Veronique Rodman, said she was not familiar with recruiting procedures for the magazine. The institute’s Web site touts its selection last November by the Washingtonian magazine as one of Washington’s “great places to work.”

The art director ad includes the address and telephone number of Mr. Zinsmeister’s farmhouse in upstate Cazenovia, which also served as his office for editing the magazine. The contact name on both ads was that of Gilbert Chesterton, better known as G.K. Chesterton. A mid-life convert to Catholicism, Chesterton, who lived from 1874 to 1936, was a novelist, journalist, and social critic known for defending religion against irreverent commentators, such as George Bernard Shaw.

An essay Mr. Zinsmeister wrote in the April 2006 issue of the American Enterprise opens with a quotation from Chesterton. “Sex is an instinct that produces an institution. That institution is the family,” the quote begins.

The Sun learned of the employment ads from former employees of Mr. Zinsmeister at the magazine.

Mr. Bush announced May 24 that after a dozen years at the helm of the magazine, Mr. Zinsmeister had agreed to take the job of assistant to the president for domestic policy. The selection was unusual, as Mr. Zinsmeister’s last government job was as a legislative assistant to Senator Moynihan more than two decades ago.

The Sun reported last month that Mr. Zinsmeister changed quotes and other passages in a profile of himself posted on his magazine’s Web site, but first published in a Syracuse newspaper. A White House spokeswoman said the appointee acted to correct errors in the original story, but Mr. Zinsmeister later told the Washington Post that it was “foolish” to make the changes himself.

In addition, the White House’s official announcement of the appointment described Mr. Zinsmeister as the founder of the magazine he edited. A liberal blog, the Horse’s Mouth, later noted that while he overhauled the magazine, he was not its founding editor.