The voting-booth curtain that preserves the secrecy of the secret ballot hasn’t become any thicker or impenetrable, but it’s harder than ever this time to picture the person behind it. Politics watchers and those working actively behind the scenes acknowledge that a lot of the assumptions about island voting habits are changing, but nobody knows by how much.

They’ll know a lot more after Aug. 9, Primary Election Day, but that will be too late for many candidates and their operatives, especially in the hotly contested Democratic races.

So a lot of people in the past few months have placed their bets on various theories about who the likely voters will be and how to reach them, all the while admitting they’re standing in the midst of a changing landscape and can’t be sure. They can’t see the forest for the trees.

Operatives were somewhat hesitant to talk on the record in mid-election, but academics and statisticians were happy to share. The race they’re watching most closely is the Democratic primary for U.S. Senate. The race boils down to the current seat holder, Brian Schatz, facing Colleen Hanabusa. Congresswoman Hanabusa is seen as the one the late U.S. Sen. Daniel Inouye had favored. For decades, he was the standard-bearer for the Americans of Japanese ancestry who led the Democratic Party.

"If she wins, that’s the status quo, but if she does poorly, that might signal the end of the old AJA machine," said Colin Moore, a University of Hawaii political science professor.

What lies behind that prognostication, which is pretty common among the experts this election cycle? One element is the changing demographic makeup of the population. Census data from 2010 indicate a growth of Hawaii’s mixed-race sector, said Eugene Tian, economic research administrator at the state Department of Business, Economic Development and Tourism.

"For the mixed population, we are No. 1 in the nation," Tian said. He was talking about the finding from the 2010 Census, that 23.6 percent of the Hawaii population, almost 1 in 4 people, identify themselves with two or more races. That’s up, if only slightly, from the 21.4 percent in 2000.

Other trends Tian is seeing include a rise in the proportion of Caucasians, from 24.3 percent to 24.7, and a significant drop in those identifying as Japanese, from 16.7 percent to 13.6 percent.

Finally, there’s age.

"In Hawaii, the population is getting older," he said. "Our percentage of 14.5 percent 65 and older makes this state 12th oldest in the nation."

These broad changes are being projected onto the electorate in various ways. Hawaii’s senior population is growing and seniors are by far the most reliable voters, according to 2012 Hawaii voter data available on Census.gov — two-thirds of those in the 60-plus age bracket vote here. By contrast, of those age 18-29, only 31 percent cast a ballot here in the last election; a larger proportion, 38 percent, were not even registered.

So one easy conclusion drawn by politicians and their handlers is that messaging to older voters is key.

Neal Milner, professor emeritus of political science at UH, sees this in many TV commercials that address Hawaii’s kupuna generation, with candidates sidling up to elders.

"I think people like me should start a rent-a-kupuna operation, to supplement my Social Security," he quipped.

Over the past few decades, Moore said, changes have left a distinct imprint on who’s expected to turn up at the primary election polls.

"The word basically is Japanese-Americans vote at the highest rates, then white people, then moving on down, depending on how long you’ve lived here in the U.S. Immigrants vote in really low rates," he added.

Although the most reliable voters can still be described as "old, white and AJAs," Moore said, "the old AJA identity has started to disappear. Ethnic voting among these groups that turn out in large numbers, that’s on the decline."

Most agree that ethnic voting, while still a significant factor, has been mitigated by intermarriage and simply the distance time has placed between descendants and the immigrant experience that shaped identity and values.

Milner thinks most of the Census changes are too marginal to create any major electoral shifts, especially along partisan lines.

"Demographics are not changing that dramatically here," Milner said. "You certainly don’t have a politically significant increase in any ethnic group.

"It’s hard to see any political significance," he added. "Whatever the demographics are, this is still one of the most partisan Democratic states in the U.S."

However, one Democratic Party consultant said privately that internal polling suggests the primary electorate, for whatever reason, is becoming more driven by issues: Voters casting ballots in the Democratic Party are trending left.

Others confirm observations of that liberal lean among the most motivated Democrats, including operatives within the opposing party. Republican consultant Dylan Nonaka said the result is the nomination of Democrats who are more left-leaning than the broader voter base. This, he said, creates an idealogical gap that the GOP can exploit, pulling at voters who are less bound to party labels, especially since the historical divides between labor and business at the rise of the Hawaii Democrats have become fuzzy with the passage of time.

"Democrats win in Hawaii because of culture," Nonaka added. "They have been taught over the years to vote for Democrats for reasons that don’t exist anymore."

How do campaigns try to seize blocs of these voters in transition? The answer seems to be: Use every tool in the toolkit.

In a state where humble grassroots campaign methods have become part of its political brand — such as Hawaii’s iconic sign-waving (see adjoining story) — the rise of more technological outreach methods is more of an addition than a replacement.

But it’s definitely steering campaigns in both parties, a trend that has strengthened as software and other tools have become cheaper and more accessible. Data collected from the electorate end up in databases that guide candidates in targeting their outreach to voters most likely to go their way.

A lot of the input comes from phone surveys, but even door-to-door campaigning can be a source. Smart-phone applications enable on-the-spot collection of facts, everything from answers to face-to-face survey questions to observations picked up around the house, Nonaka said. American flag out front? Pro-life bumper sticker on the car? Into the database it goes.

And, said GOP Hawaii Executive Director Blake Parsons, since 2012 Republicans have been converted to high-tech ways of gathering data. The party locally is using phone banks equipped with Internet phones that do the dialing much more efficiently, he said, and in campaigning, every second counts.

Ultimately the technology is more about the data mining and less about the message delivery — e-mail blasts, Facebooking, Twitter posts or whatever. But, Milner said, social-media modes are effective in reaching people who use it.

"One thing you can do with social media that you can’t do with sign-waving is build networks out of it," he said.

The association of political messaging with people known to the voters is another strength of social media, Moore added. People respond better to a candidate once they feel they’ve been properly introduced.

"I think it can be pretty effective — it has some of the same qualities a door-to-door campaign does," he said. "A lot of people are pretty surprised to find out about the politics of friends. And you are more likely to support a candidate if it’s recommended to you by a friend or relative."

That said, nothing replaces the truly personal touch: meeting the candidate. Everyone agrees that candidates walking the district reap the biggest dividends.

"The most effective way is still absolutely knocking on doors," Moore said. "These robo calls are basically useless. The old-fashioned shoe-leather politics, it works better than anything else."