A publisher once told writer H.L. Mencken that there were four kinds of books that seldom, if ever, lost money in America: “first, murder stories; secondly, novels in which the heroine is forcibly overcome by the hero; thirdly, volumes on spiritualism, occultism and other such claptrap; and fourthly, books on Lincoln.”

Not much has changed in 80 years.

Slap Lincoln’s craggy face on a book cover, come up with an angle that hasn’t been done at least 800 times, and you are going to move some product.

But it’s not just money that motivates some writers. Authors often exploit great men of history to score political and cultural points – more so, I suspect, in an age when one political viewpoint dominates academia, and historical facts are routinely twisted out of their context to advance that viewpoint, in a process politely called revisionism.

Such an effort to make a point would seem to be behind “The Intimate World of Abraham Lincoln.” It was written by a now-deceased therapist named C.A. Tripp, author of the 1975 book “The Homosexual Matrix.” The new 384-page book argues from what seems flimsy evidence that “A. Lincoln” (how he signed his name) was gay Lincoln.

The book might have been an amusing and little-noticed curiosity had it argued, say, that Lincoln was a crypto-fascist or suffered from ADD. But because sexual orientation looms so large in the landscape of modern politics – and because Lincoln is always of interest – the book has been taken up by reviewers nationwide and debated seriously in various journals of modern culture and politics. The sneaking suspicion that Lincoln was gay has probably entered the public mind by now.

This would appear to be an important question politically, in some circles: If a man who was arguably the greatest of American presidents, and the first Republican to hold that office, was homosexual, it would tend to undercut some of the antics of the right, including a constitutional amendment limiting marriage to men and women.

But that’s not history.

The Lincoln-was-gay argument seems to rest heavily on the fact that he shared a bed at times with men, that he was excruciatingly shy around the opposite sex, and that his marriage was at times an unhappy one. What this seems to miss is context – and, without context, one can profoundly misread the record. In 19th century America, in the days before central heating and suburban tract development, men often slept together, in lonely pioneer settlements and even crowded cities where there were few bedrooms available. That didn’t mean they were lovers. A modern lens can grotesquely distort the past.

John Adams and Benjamin Franklin famously shared a bed, and debated whether the window should be left open, without spurring assertions – to my knowledge – that they were bisexual. Laurel and Hardy often slept together in their movies of the 1920s and ’30s, without any apparent implication of homosexual leanings.

Should their film characters be “outed”? One could doubtless search the record of, say, Chester A. Arthur and Millard Fillmore for similar episodes of befriending, and bunking with, males. But those presidents wouldn’t sell many books or advance an agenda.

And many a young man – now as well as then – who lusts after the opposite sex finds himself tongue-tied around women. Some of them are transported into stormy marriages.

Of course, Lincoln is a compelling figure, not only for his immensely important historic role, but because he was a fascinating character: given both to self-doubt and deep conviction, often moody and depressed, bitterly cynical but profoundly patriotic, hilariously funny on occasion, intensely private, a beautiful writer drenched in the idiom of Shakespeare and the Bible but unable to accept conventional wisdom on religious and other matters. He may have had male lovers, for all we know _ but we don’t know. And the full record would tend to argue Lincoln had a more conventional 19th century sex life, complete with (at times) painful marriage.

Should we care about Lincoln’s activities in bed? Perhaps. No historic figure has a “right” to a private life. Though one could question how much a great man’s sex life influences history, the record can be raked over for clues by anyone.

But the rampant politicization of the past does offend. Mr. Tripp’s expertise and passion were in promoting homosexuality as a normal human activity, rather than as it was once seen: a mental disorder. Most Americans these days would fully embrace his more tolerant and sympathetic approach to human nature, but that interest and background obviously colored – indeed, dictated – Mr. Tripp’s evaluation of Lincoln’s life.

Those who write history are among the most important people in our society. It is only through their work that we grasp the past and understand the price of freedom. The men and women of the profession worth admiring do not pick out facts that support an agenda or make a great figure dance to their tune. They fearlessly follow – to the extent human beings can be objective – where the facts lead.

There’s a real difference.

Edward Achorn is The Providence Journal’s deputy editorial-pages editor. His e-mail address is eachorn (at) projo.com.