If you are wondering about Donald Trump's temperament after some of his remarks, you might want to compare it with Hillary Clinton's.
On a daily basis, Hillary treats the Secret Service agents who protect her with such nastiness and contempt that being assigned to her detail is considered a form of punishment.
For my book "The First Family Detail: Secret Service Agents Reveal the Hidden Lives of the Presidents," agents who would give their lives for her described the living hell of dealing with Hillary.
When in public, Hillary smiles and acts graciously. As soon as the cameras are gone, her unbalanced personality, nastiness, and imperiousness become evident.
During the height of the Monica Lewinsky scandal, a Secret Service uniformed officer was standing post on the South Lawn when Hillary arrived by limo.
"The first lady steps out of the limo, and another uniformed officer says to her, 'Good morning, ma'am,' " a former uniformed officer recalls. "Her response to him was '[expletive] off.' I couldn't believe I heard it."
Everyone on her detail recalls the fate of Christopher B. Emery, a White House usher who made the mistake of returning Barbara Bush's call after she had left the White House. Mr. Emery had helped Barbara learn to use her laptop. Now the former first lady was having computer trouble. Twice, Mr. Emery helped her out. For that, Hillary Clinton fired him. The father of four, Mr. Emery could not find another job for a year.
"We were basically told, the Clintons don't want to see you, they don't want to hear you, get out of the way," says a former Secret Service agent. "If Hillary was walking down a hall, you were supposed to hide behind drapes used as partitions. Supervisors would tell us, 'Listen, stand behind this curtain. They're coming,' or 'Just stand out of the way, don't be seen.' "
Hillary had a "standing rule that no one spoke to her when she was going from one location to another," says former FBI agent Coy Copeland. "In fact, anyone who would see her coming would just step into the first available office."
An agent working with Mr. Copeland for independent counsel Kenneth W. Starr's investigation of the Clintons' investments in the Whitewater real estate development did not know the rules: He made the mistake of addressing Hillary, saying "Good morning, Mrs. Clinton" as she passed him in a corridor of the Eisenhower Executive Office Building.
"She jumped all over him," Mr. Copeland says. " 'How dare you? You people are just destroying my husband.' It was that vast right-wing conspiracy rant. Then she had to tack on something to the effect of 'And where do you buy your suits? Penney's?' "
For weeks, the agent told no one about the encounter. "Finally, he told me about it," Mr. Copeland says. "And he said, 'I was wearing the best suit I owned.' "
"Hillary was very rude to agents, and she didn't appear to like law enforcement or the military," says former Secret Service agent Lloyd Bulman. "She wouldn't go over and meet military people or police officers, as most protectees do. She was just really rude to almost everybody. She'd act like she didn't want you around, like you were beneath her."
At the 2000 Democratic National Convention at the Staples Center in Los Angeles, Secret Service agents were told that the Clintons had issued instructions that agents leave their posts and, as if they were muggers, step around corners to hide as the Clintons approached.
"We were told they didn't want to see us," an agent on the detail says.
"Hillary never talked to us," says another agent who was on her detail. "Most all members of first families would talk to us and smile. She never did that."
"Hillary would cuss at Secret Service drivers for going over bumps," former agent Jeff Crane says.
On top of that, Secret Service agents are forced to coordinate her visits back to her Chappaqua, N.Y. home so she does not run into Bill Clinton's busty, blonde mistress, unofficially code-named "Energizer" by agents.
"There's not an agent in the service who wants to be in Hillary's detail," a current agent says. "If agents get the nod to go to her detail, that's considered a form of punishment among the agents. She's hard to work around, she's known to snap at agents and yell at agents and dress them down to their faces, and they just have to be humble and say, 'Yes ma'am,' and walk away."
The agent adds, "Agents don't deserve that. They're there to do a job, they're there to protect her, they'll lay their life down for hers, and there's absolutely no respect for that. And that's why agents do not want to go to her detail."
Hillary claims she will be the champion of the middle class and the so-called little people. The truth is she treats the little people like dirt and seems to derive pleasure from making their lives miserable.
No one would hire at a McDonald's someone who treats others in such a shoddy, nasty manner, yet Hillary Clinton is running for president.
• Ronald Kessler, a former Washington Post and Wall Street Journal investigative reporter, is the author of "The First Family Detail: Secret Service Agents Reveal the Hidden Lives of the Presidents" (Crown Forum, 2015).