Mark Moyar doesn’t exactly fit the stereotype of a disappointed job seeker. He is an Eagle Scout who earned a summa cum laude degree from Harvard, graduating first in the history department before earning a doctorate at the University of Cambridge in England. Before he had even begun graduate school, he had published his first book and landed a contract for his second book. Distinguished professors at Harvard and Cambridge wrote stellar letters of recommendation for him.

Yet over five years, this conservative military and diplomatic historian applied for more than 150 tenure-track academic jobs, and most declined him a preliminary interview. During a search at University of Texas at El Paso in 2005, Mr. Moyar did not receive an interview for a job in American diplomatic history, but one scholar who did wrote her dissertation on “The American Film Industry and the Spanish-Speaking Market During the Transition to Sound, 1929-1936.” At Rochester Institute of Technology in 2004, Mr. Moyar lost out to a candidate who had given a presentation on “promiscuous bathing” and “attire, hygiene and discourses of civilization in Early American-Japanese Relations.”

It’s an example, some say, of the difficulties faced by academics who are seen as bucking the liberal ethos on campus and perhaps the reason that history departments at places like Duke had 32 Democrats and zero Republicans, according to statistics published by the Duke Conservative Union around the time Mr. Moyar tried to get an interview there.

Issues relating to hiring and promotion are “a constant complaint from those on the conservative spectrum in academe,” the president of the National Association of Scholars, Stephen Balch, said.

Mr. Moyar is used to opposition. A contrarian among most Vietnam scholars, he does not believe it was a mistake for America to have gone into Vietnam. In carefully argued prose using previously unexamined sources, he marshals support for the “domino theory.” His scholarship and books have received great reviews and marked him as a rising star.

In saying Vietnam was winnable, Mr. Moyar is “profaning one of the holy of holies,” Mr. Balch said. Senator Webb, a Democratic opponent of the Iraq war, and scholar William Stueck, a liberal, have endorsed Mr. Moyar’s book, “Triumph Forsaken” (Cambridge), which was the subject of a conference at Williams College. A conference is a signal honor for a young scholar.

Mr. Moyar says he was the object of political discrimination at Texas Tech in 2005. The chairman of the history department there, Jorge Iber, said he “disagreed wholeheartedly” with Mr. Moyar’s assertion. Mr. Iber, who is a conservative Republican, said the department makes its decisions on the basis of individual merit.

A history professor at Texas Tech, John Reckner, declined to speak about specifics of Mr. Moyar’s job application at that particular school, but noted generally, “Let’s just say, a person applying to teach whose topic is the Vietnam War and whose position is conservative, would encounter difficulties because the ideological ghosts of the 1960s are, unfortunately, still alive on a great many campuses, even though the Vietnamese themselves have put the war behind them.”

On April 27, 2005, 15 faculty members out of the 20 in Texas Tech’s history department voted Mr. Moyar “unacceptable.”

Texas Tech is not the only institution in the Lone Star State where Mr. Moyar says he received differential treatment. Another is, of all places, the George Bush School of Government and Public Service at Texas A&M University. Named after the 41st president, it is where Mr. Moyar worked as a postdoctoral fellow and lecturer in 2003 and 2004. Dean Richard Chilcoat, a retired lieutenant general, disputed the idea that that school’s faculty is overwhelmingly liberal.

Mr. Moyar said Mr. Chilcoat initially told him the good news that all three finalists were considered qualified, but that he, unfortunately, was not at the top, only to learn later that he was unranked among the three finalists and found unacceptable by three faculty members. Mr. Chilcoat told The New York Sun that maybe there was miscommunication.

Mr. Moyar alleges that the job description was changed from the one originally advertised. Mr. Chilcoat said that after a national search, the school made the hire based on the published criteria.

Mr. Moyar says he was surprised to learn one objection raised against him was that he would not have an “immediate impact,” yet his second book was published before the second book of the no. 1 candidate and before the first book of the no. 2 candidate. He says he was not told why he had been unranked.

Mr. Chilcoat declined to talk about confidential deliberations, but said in no way was ideology or politics a consideration in the voting. “I would never allow any discrimination,” he told the Sun. He said Mr. Moyar was not “de-selected” but was a competent historian who got a fair opportunity to compete. “When you added everything up, he was not the best qualified,” he said.

Mr. Moyar said Mr. Chilcoat didn’t reply to him during his final five months there. Mr. Chilcoat said, “I always made sure he knew what my position was.”

Mr. Moyar told the Sun that one faculty member informed him she did not vote for him because of “ideological differences.” Documents obtained by Mr. Moyar through the Texas Public Information Act and shared with the Sun show an anonymous faculty candidate assessment describing Mr. Moyar as a revisionist historian “bent on proving the merits of the Vietnam War (even if he is doing a great job doing it). His being here would hurt the reputation of the school.” Another faculty member expressed concern about “his agenda-oriented research.”

The dean of the faculties at Texas A&M, Karan Watson, wrote to Mr. Moyar saying no evidence presented indicated that illegal discrimination occurred.

Mr. Moyar’s credentials were of little help at Old Dominion, where he learned he was considered more a diplomatic historian than military. At Miami University of Ohio, the history department evaluated his scholarship to be more strongly in the field of military history than American foreign policy. This was despite his having taught courses in American foreign policy and having letters of recommendation from two of the world’s top historians of American foreign relations: Akira Iriye and Ernest May, both of Harvard.

The new president of Miami University, David Hodge, wrote to Mr. Moyar saying the school took seriously its obligation to hire the best faculty “without regard to personal attributes, including political beliefs.”

In applying to the U.S. Air Force War College in 2003, Mr. Moyar said a professor, Jeffrey Record, repeatedly failed to contact Mr. Moyar to set up a visit to the college. Mr. Record told the Sun it was not his job to set up the visit but that he was a “polite and gracious” host to Mr. Moyar.

Mr. Moyar says that after he delivered a presentation, Mr. Record told him that he was “full of [excrement].” Mr. Record told the Sun that he “flatly denies” this, but said if he did say something like that, it was purely in jest and people who know him would know it was in jest. Mr. Record said he regards Mr. Moyar’s work as serious and scholarly although he disagrees with it.

Asked about the treatment of conservatives in academia, a professor at Columbia University, Eric Foner, said he did not know Mr. Moyar, but he said most history departments do not know or care about the politics of candidates. Mr. Foner, who leans to the left, said conservatives should stop complaining about being victims, which they blame liberals for doing. A professor at Boston College, Alan Wolfe, told the Sun that academic departments tend to hire like-minded people. He said there were surely liberal history departments, but so too conservative political science departments. “There is insufficient intellectual diversity at both liberal Ivy League colleges and as well as conservative colleges like Hillsdale and Grove City College,” he said.

A professor at Duke University, Michael Munger, who leans to the right, said that, paradoxically, liberal students benefit most from conservative faculty. Otherwise, he said, in learning how to make arguments, “they don’t get to play against the first team.”

An emeritus professor of government at Smith College, Stanley Rothman, said he could not speak to individual cases but that a study he co-authored in 2005 called “Politics and Professional Advancement Among College Faculty” seemed to show that statistically, conservatives were not treated as well as liberals in the academy.

The president of the Foundation for Individual Rights in Education, Gregory Lukianoff, said universities can “take brutal advantage” of the fact that most tenure and promotion decisions are confidential. An attorney at Alliance Defense Fund, David French, a Christian public interest law firm, said ideologically based discrimination cases, such as race- and gender-based cases, weigh direct evidence and circumstantial evidence of differential treatment. He said that once private institutions advertise for a specific job, they are required to live up to that description. A New York attorney, Jeffrey Duban, said judges look at whether a decision against a faculty applicant was arbitrary or capricious.

This month, Mr. Moyar filed a complaint with the University of Iowa’s Office of Equal Opportunity and Diversity after he was not selected for an interview for a job in diplomatic history. He found among county voting records that the department had 27 Democrats, no Republicans, two with no voting affiliation, and four not listed. The university has a policy prohibiting discrimination in employment based on “associational preference” along with other things like race and creed.

Mr. Moyar said, “It’s extremely unhealthy for the country to have one-half of the political spectrum absent from higher education.” Mr. Moyar now holds a chair at the U.S. Marine Corps University at Quantico, Va.

Mr. Moyar said he wants to help other scholars in the future “who are going to have to deal with this nonsense.” He said he knew going into the history field, it would be bad. “But I had assumed there would be room for a few token conservatives,” he said.