The revolving door of politics is whirling at such a dizzying pace. No wonder voters can’t seem to get their bearings.

What should they expect of a candidate who runs for elected office? That they’ll finish out the full term?

Of course, that’s never been a safe assumption. Truncated terms of office have always been a feature of the political landscape. Further, imposing extreme hurdles for elected officials who want to resign — forcing them to pay special-election costs, for example, as some frustrated voters have proposed — will discourage many qualified candidates from seeking office. Attracting good talent to public service is hard enough as it is.

But the credibility of campaign pledges to serve has taken a particular beating in the last few years.

Setting aside the unpredictable churn of openings that occur because of deaths in office — and there have been two on the City Council in less than two years — there have been opportunistic departures. U.S. Rep. Neil Abercrombie left office early, as did Mayor Mufi Hannemann.

And at each of those points of upheaval, a special election had to be called, some within a normal election cycle, some incurring additional expense.

The latest is City Council Chairman Todd Apo. This week he decided to leave politics for a job in public affairs for Walt Disney Parks and Resorts, now developing a Kapolei resort. Certainly it’s better that he leave office rather than remain and try to navigate conflicts of interest; this bombshell, however, was dropped amid voters already weary of politicians jumping ship.

The further complication in Apo’s case is that his job offer came on the cusp of key deadlines: With a little push, it would have been possible to schedule balloting for his replacement to coincide with the general election. As it is, Apo said he wanted to remain long enough to help oversee the discussions on rescinding the homeowner tax classification, fireworks legislation and other pending issues.

Thus the taxpayer will have to pay for the $175,000 cost of a special election. Although Apo said the funds are available in the city clerk’s budget, the bottom line is that this remains an unfortunate outcome. The money will have to be replenished, and the bill lands at the taxpayers’ feet.

The only element that mitigates in Apo’s favor is the burden on his potential replacement. Ginning up a special election campaign between now and November would be a heavy lift for all but the candidates with monied connections. Postponing it will make a lower-cost grassroots campaign more affordable for average political hopefuls.

Regardless, the necessity of yet another special election saps a resource even scarcer than public funds: public trust. The voters surely are asking themselves: Why bother to invest support in these candidates when they may pull up stakes at will?

It is incumbent on these voters, then, to press candidates on their commitment to elected office — which, after all, should be a higher calling than simply pursuing career goals — before rewarding them with their support.