Mitchell E. Daniels Jr., who had pledged to remain nonpartisan after he made the transition from Indiana's Republican governor to Purdue University's president, said on Thursday that his recent decision to give a paid speech to a conservative think tank showed poor judgment.
Mr. Daniels has been on the defensive for the past several days, following reports that he delivered the keynote speech on Monday at the Center of the American Experiment, in Minneapolis. The group describes itself as a "nonpartisan, tax-exempt, public-policy and educational institution that brings conservative and free-market ideas to bear on the hardest problems facing Minnesota and the nation."
In a letter published on Thursday in the Journal & Courier, of Lafayette, Ind., Mr. Daniels said he had found criticism of his actions to be "persuasive."
"I accept the validity of the criticism," he wrote, "and will try to avoid similar judgment errors in the future."
The exact content of Mr. Daniels's speech is not known, but he described it as "scrupulously nonpartisan."
"Its themes," he wrote, "were how to deliver basic services effectively, how to bring people together across political lines, the importance of civility in public discourse, and the centrality of social mobility and opportunity for the yet-to-haves in our society as goals of public policy."
Mr. Daniels did not disclose what he had been paid for the speech, but said he would give the proceeds to scholarships at Purdue.
The former governor said he had violated no university policy or tenets of his contract, but he acknowledged that he had created a perception problem.
"Facts and rules aren't the determining factor here," he wrote. "Perceptions, and understandable misperceptions, matter even more."
Mr. Daniels's politics have sparked sporadic controversies at the university, where he took the helm as president in January.
In July the Associated Press published e-mails showing that Mr. Daniels, during his time as governor, had tried to purge the writings of Howard Zinn, a liberal scholar, from classroom curriculums.