A state's lieutenant governor is "almost like your appendix," says Ed Feigenbaum, a national expert on lieutenant governors and publisher of a newsletter on Indiana politics. "You don't notice it until there's a problem or you need it for something."

But lately, lieutenant governors are getting noticed a lot. And they're not getting the type of attention they'd like. Since February, three lieutenant governors have resigned from office amid scandal.

It started with Nebraska Lieutenant Gov. Rick Sheehy who resigned after the press revealed he had made thousands of late-night phone calls to four women -- none of whom were his wife -- on his state-issued mobile phone. He was considered the front-runner in the 2014 gubernatorial election.

Then came Florida Lieutenant Gov. Jennifer Carroll, who quit her job after police questioned her about ties to a veterans charity that was allegedly part of a $300 million racketeering operation. Carroll had a once-promising career as the first black woman elected to the state legislature as well as the lieutenant governor's office.

She was no stranger to controversy. A former aide once alleged that she was fired after complaining to the media that she walked in on Carroll and a staffer engaged in a sex act. She's also been accused of having excessive travel expenses.

Most recently, Massachusetts Lieutenant Gov. Timothy Murray resigned effective Sunday. He had once been considered a likely successor to Gov. Deval Patrick, but his star fell due to questions about a car crash in 2011. He initially said he wasn't speeding, but an investigation later revealed he was traveling 100 miles per hour in his state-issued vehicle.

Murray also faced continued scrutiny about allegations of improper campaign fundraising on his behalf by a public housing official. He will now lead the Worcester Regional Chamber of Commerce and insists those controversies aren't the reason he left office.

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So what does it mean that in a span of just a few months, three lieutenant governors have resigned?

Julia Hurst, executive director of the National Lieutenant Governors Association, says it doesn't mean much of anything.

"The office of lieutenant governor is arguably the most diverse office in the nation," Hurst wrote in an e-mail to Governing. "The three resignations are different situations occurring in different offices in different states in three different regions of the country at different points of terms in office. My conclusion would be coincidence."

But Ray Scheppach, the former longtime leader of the National Governors Association, says there may be something to the trend.

"I think what happens is, any time there's a little problem, the governor (can) jettison the person quickly," says Scheppach, now a professor with University of Virginia's public policy program. "A lot of times the governor is forced to accept the person just because of the politics of the state. Sometimes they run together. Sometimes they don't. But ... any little blip, and they're out of there."

Recent comments from Carroll seem to underscore that point. She told the press that she resigned -- despite believing she did nothing wrong -- because Scott's staff asked her to, and she is a team player. "[I]f your boss came to you and said 'I want you to resign' and knowing that you're going to have opposition ... or animosity in an office area, is that what you would do? Would you stay and put up with that consequence?" she said.

A similar dynamic emerged in the wake of the Nebraska scandal. When Gov. Dave Heineman announced the resignation of Sheehy, his running mate, he stated simply, "I had trusted him, and that trust was broken."

Often a lieutenant governor's fate is closely tied to the governor's vision of the office since the role is not always fully defined in the law. "They don't have a lot of statutory or constitutional responsibility," Feigenbaum says. "It's kind of at the mercy of his or her governor to assign his or her task." For a lieutenant governor on the outs with the governor, resignation may be the best option at that point.

And, Feigenbaum says, governors often don't have the sort of close ties to their lieutenants that could help spare a public official who's in the midst of controversy. "It can be a tenuous relationship to begin with," he says. "The fact that they're the same party doesn't mean anything."

Indeed, the lieutenant governor's office is rarely a high-profile one, and the very fact that the recent spat of resignations isn't a national scandal is probably a testament to that.

Scheppach says the office has a unique political component, in that a governor risks being shown up if the lieutenant governor does well and risks being dragged down if the lieutenant governor is in a scandal. In other words, for a governor, there's not much political upside to a great lieutenant, but there's a huge downside to a bad one. "That's why they [governors] cut their losses real quickly," Scheppach says.

Moreover, it would seem that the traditional makeup of the office -- held by an ambitious person, often with an undefined role, and largely operating out of the spotlight -- would seem to be a recipe for potential problems.

Still, it's unclear whether any generalizations can be made about these particular resignations. "I find it impossible to derive a conclusion," Richard Ravitch, former lieutenant governor of New York, tells Governing.

Feigenbaum agreed with Ravitch's thoughts. But he also noted lieutenant governor resignations aren't necessarily rare. Often, he says, the officials quit because they're bored. "It's happened quite a bit more frequently than you'd think," Feigenbaum says, "and not necessarily because of scandals."