There was an interesting poll result about Hillary Clinton last week. According to a Quinnipiac poll, 60 percent of independent voters believe that she has strong leadership qualities. But when these same voters were asked if she is honest and trustworthy, the evaluations flipped. Sixty-one percent said she is not honest and trustworthy. Apparently there are a lot of Americans who believe that Hillary Clinton is dishonest and untrustworthy but also a strong leader.

Let’s set aside her specific case for a second. These poll results raise a larger question: Can you be a bad person but a strong leader?

The case for that proposition is reasonably straightforward. Politics is a tough, brutal arena. People play by the rules of the jungle. Sometimes to get anything done, a leader has to push, bully, intimidate, elide the truth. The qualities that make you a good person in private life --- kindness, humility and a capacity for introspection --- can be drawbacks on the public stage. Electing a president is different than finding a friend or lover. It’s better to hire a ruthless person to do a hard job.

I get that argument, but outside the make-believe world of “House of Cards,” it’s usually wrong. Voting for someone with bad private morals is like setting off on a battleship with awesome guns and a rotting hull. There’s a good chance you’re going to sink before the voyage is over.

People who are dishonest, unkind and inconsiderate have trouble attracting and retaining good people to their team. They tend to have sleazy friends. They may be personally canny, but they are almost always surrounded by sycophants and second-raters who kick up scandal and undermine the leader’s effectiveness.

Leaders who lack humility are fragile. Their pride is bloated and sensitive. People are never treating them as respectfully as they think they deserve. They become consumed with resentments. They treat politics as battle, armor up and wall themselves off to information and feedback.

You may think they are championing your cause or agenda, but when the fur is flying, they are really only interested in defending themselves. They keep an enemies list and life becomes a matter of settling scores and imagining conspiracies. They jettison any policy that might hurt their standing.

It is a paradox of politics that the people who set out obsessively to succeed in it usually end up sabotaging themselves. They treat each relationship as a transaction and don’t generate loyalty. They lose any honest internal voice. After a while they can’t accurately perceive themselves or their situation. Sooner or later their Watergate will come.

Maybe once upon a time there was an environment in which ruthless Machiavellians had room to work their dark arts, but we don’t live in Renaissance Italy. We live in a world of universal media attention. Once there is a hint of scandal of any kind, the political world goes into maximum frenzy and everything stops.

We live in a world in which power is dispersed. You can’t intimidate people by chopping your enemies to bits in the town square. Even the presidency isn’t a powerful enough office to allow a leader to rule by fear. You have to build coalitions by appealing to people’s self-interest and by luring them voluntarily to your side.

Modern politics, like private morality, is about building trust and enduring personal relationships. That means being fair, empathetic, honest and trustworthy. If you stink at establishing trust, you stink at politics.

People with good private morality are better at navigating for the long term. They genuinely love causes beyond themselves. When the news cycle distracts and the short-term passions surge, they can still steer by that distant star. They’re less likely to overreact and do something stupid.

People with astute moral sentiments have an early warning system. They don’t have to think through the dangers of tit-for-tat favor-exchanges with billionaires. They have an aesthetic revulsion against people who seem icky and situations that are distasteful, which heads off a lot of trouble.

Of course, private morality is not enough. You have to know how to react to unprincipled people who want to destroy you.

But, historically, most effective leaders --- like, say, George Washington, Theodore Roosevelt and Winston Churchill --- had a dual consciousness. They had an earnest, inner moral voice capable of radical self-awareness, rectitude and great compassion. They also had a pragmatic, canny outer voice. These two voices were in constant conversation, checking each other, probing for synthesis, wise as a serpent and innocent as a dove.

I don’t know if Hillary Clinton possesses this double-mindedness. But I do know that if candidates don’t acquire a moral compass outside of politics, they’re not going to get it in the White House, and they won’t be effective there.