One of Hillary Clinton's greatest struggles in the 2016 election was answering this simple question: Why do you want to be president?

Her campaign churned out various responses to this obvious and well-worn inquiry, but nothing that stuck. This was a problem from day one, according to Jonathan Allen and Amie Parnes' Shattered: Inside Hillary Clinton's Doomed Campaign.

It has been almost a year since Election Day. Clinton has published a 500-plus-page book, titled What Happened, recounting 2016 from her point of view.

She still can't say why she wanted to be president.

"I ran for President because I thought I'd be good at the job," she writes in her new book. "I thought that of all the people who might run, I had the most relevant experience, meaningful accomplishments, and ambitious but achievable proposals, as well as the temperament to get things done in Washington."

A good political response, but believing in one's own competence hardly explains the why of one's candidacy.

Clinton also claims she was unfairly targeted, writing in an aside about all the people who asked her about running, "The implication was that there must be something else going on, some dark ambition and craving for power."

"Nobody psychoanalyzed Marco Rubio, Ted Cruz, or Bernie Sanders about why they ran. It was just accepted as normal," she added.

That's simply not true. Those candidates also had their White House ambitions questioned and analyzed by the press.

Fox News' Sean Hannity, for example, asked Sen. Marco Rubio, R-Florida, point-blank on April 13, 2016, "Why do you want to run for president of the United States?" There is more where that came from.

Sen. Ted Cruz not only had his motivations examined, but the press also investigated Donald Trump's suggestion that the Texas Republican wasn't even eligible to run.

There was also no shortage of reports and op-eds questioning Sen. Bernie Sanders, I-Vt., reasons for sticking it out in the Democratic primaries.

It's telling that Clinton would allege a shady, sexist conspiracy rather than consider the possibility that people kept asking her why she was running because she never offered an articulate answer. Perhaps Cruz, Rubio and Sanders were asked the same question fewer times because the press did not consider them shoe-ins for their respective party's nominations. Also, the senators offered fairly succinct responses that didn't change from day-to-day.

It's even more telling that Clinton still can't give a clear answer to the question.

In What Happened, the former secretary of state claims she ran because she wanted to strengthen the U.S. economy. She claims she ran because someone at an event several years ago once whispered in her ear, "Dare to compete." She claims she ran because she was encouraged by President Obama. She claims she ran because she was encouraged by former Obama election gurus John Podesta and David Plouffe. She claims she ran because it was "too important to pass up." She claims she wanted to help people.

She sprays the reader down with so many vague reasons for why she jumped into the race that one is left with no clearer idea of the reason for her candidacy than when one first picked up her book.

"It was a chance to do the most good I would ever be able to do. In just one day at the White House, you can get more done for more people than in months anywhere else," Clinton writes, adding, "I came back to the part that's most important to me. We Methodists are taught to ‘do all the good you can.' I knew that if l ran and won, I could do a world of good and help an awful lot of people."

In the end, she takes up an entire chapter (18 pages) trying to explain the existence of her failed 2016 campaign. It's winding and long-winded, and it includes everything from improbable personal anecdotes to her recycling her old campaign slogans. But it mostly says a whole lot of nothing.

It's all rather remarkable, especially considering how much it emphasizes the differences between Clinton's and Trump's messages and abilities.

Say what you want about Trump, but the man knows how to sell a vision (there's a reason why the world is dotted with buildings bearing his name). We all know why he wanted to be president. He was able to distill his pitch into four simple words, which were distilled further into a popular and widely used acronym. Trump ran because he wanted to "Make America Great Again." It's an obvious call to arms in the culture war, and it was not lost on the GOP base. Not too shabby for a guy who had never run for public office before.

Clinton, on the other hand, never quite explained the why of her candidacy during the election, and her book doesn't make it any clearer. The best anyone can tell is that she jumped into the ring because she wanted to make an "economy that works for everyone" (whatever that means), because she believed she was competent and because President Obama said so.

Something like that.