In Assassin of Shadows (Pegasus Crime, June; reviewed on p. 50), Goldstone casts the murder of President McKinley in a new light.

What gave you the idea to center on an inquiry into a possible conspiracy behind McKinley’s assassination?

I’m always on the lookout for an incident where the history can be absolutely accurate and yield a plot that is both possible and plausible. The McKinley assassination was perfect, because so many questions have been insufficiently addressed.

How did you come up with the conspiracy that’s investigated in the book?

At the time, most people in power assumed the McKinley shooting was part of an anarchist conspiracy, and any number of people were arrested and questioned, much of which I detail in the book. That theory turned out to be false, and the supposed conspirators were reluctantly freed. Questions were asked, but much more quietly, about the, shall we say, odd behavior of McKinley’s bodyguards, but their explanations, which seemed to me problematic, were accepted without a lot of digging. Some historians have certainly pointed this out, but without any hard evidence, it’s difficult to take that further. One of the reasons I’m drawn to fiction is that I get to explore some theories for which there’s not adequate evidence to do as straight history.

Had protection of the president after two previous presidential assassinations become more robust?

Options were limited. Most presidents of that era insisted on pressing the flesh, so avoiding public exposure was out of the question. In this case, precautions were taken—well-wishers were forced into a single line, and Secret Service agents flanked McKinley. Both John Wilkes Booth and Charles Guiteau, the man who assassinated President Garfield, had shot from extremely close range, so the thinking was, if you secure the immediate area, you’ve largely eliminated the threat. In McKinley’s case, of course, while the theory remained sound—Leon Czolgosz also shot from close range—there was a failure in performance. Just why that occurred is the basis of my book.

What do you think McKinley’s significance is for our history?

Other than presiding over the Spanish-American War and the annexation of Hawaii, there are not many other notable highlights of his years in office. But in some ways that was his greatest achievement—the nation ran smoothly and solidified itself as an economic and military power during his tenure, an era of relative prosperity sandwiched between the Panic of 1893 and the Panic of 1907.