HARPSWELL — Supporters of ranked-choice voting (Question 5 on the statewide ballot Nov. 8) have revealed two important facts about the proposal.

First, they believe that using it will change voter behavior and make us get along better politically with one another.

Second, they implicitly acknowledge that it is complicated and unprecedented by running a series of mock elections to select people’s favorite beer.

But they have missed two important facts.

Ranked-choice voting is more expensive than either the current election system or any accepted alternative to plurality elections in which the candidate with the most votes wins.

And the proposed system is undemocratic and far more vulnerable to tampering than the current system.

Let’s take a closer look.

In order to win a ranked-choice election, a candidate might need the second- and third-place votes from supporters of other candidates. Supporters think that candidates will go easy on one another to pick up those votes. That would bring a change in the political atmosphere, they say.

But today’s deep partisan divisions are not likely so easily to give way to political peace. It may prove difficult for ideological candidates to gain backup support. Portland’s nonpartisan mayoral race is a poor predictor of party politics.

In fact, if candidates line up deeply divided on the issues, it is far from sure that in critical elections, voters will cast even second-choice votes.

The state needs a system that will produce compromises, but that won’t happen because of what is essentially a vote-counting gimmick. Forging compromises is a question of leadership.

The complexity of ranked-choice voting is obvious. Instead of simply voting for the candidate you prefer, each voter must have an election strategy. They have to guess at what will happen to their backup votes.

For example, in a four-way race, a voter who had supported only the first two candidates eliminated would then be stripped of any role in the ultimate election. To have their votes count in the last round, they would have had to vote for their first- and third-favorite choices, skipping the second. Confusing? Absolutely.

Proponents forecast a change in human behavior because of their system. But using such forecasts as the main argument in favor of a proposal is risky.

Then there’s the higher cost of ranked-choice voting. According to the Maine Secretary of State’s Office, the cost to the state of such an election would be about $910,000 in the first year, compared with $248,000 under the current system.

If Maine allowed a runoff election between the two highest vote getters, the cost would be only twice the current amount.

Another solution would be to have all candidates run in a single primary with the top two running in the general election. Used in California, that system would cost a bit less than today.

Though the focus is on the governor’s race, at any one election there could be as many as 190 ranked-choice races to count: the governor, a U.S. senator, two U.S. House members and 186 members of the Maine Legislature. Any single voter could face a ballot with five ranked-choice votes.

One of the reasons for the higher cost of ranked-choice elections is the need to transport all ballots to a single counting location. They would then be run through a computer. Contrast that with more than 450 voting locations today, where the votes can be checked by direct viewing and the results easily totaled.

A single computer would be far more vulnerable to tampering. And any foul play would be invisible and might not be discovered for months or years after the election.

Finally, there’s the matter of democracy itself. In the current system, a runoff or a top-two primary, voters can understand the consequences of their choices. In ranked-choice voting, voters cannot foresee the effect of their second- and third-choice votes.

Ranked-choice voting is not used in any federal or state election. Plurality voting, as in Maine, is used in 39 states. The rest use some form of runoff.

The reason is simple. In any currently used system, voters know the consequences of their votes. By contrast, ranked-choice voting is a costly shot in the dark.