ON THE NET Company that organized online voting: http://www.election.com Arizona Democratic Party: http://www.azdem.org

PHOENIX -- Thousands of voters in Arizona's Democratic presidential primary showed the world Internet voting can work on a small scale. Now, the question is whether much bigger groups can join in.

One way or the other, critics and supporters agree that eventually, most Americans will have the option of voting for their leaders by clicking a computer mouse.

"We opened up the gates today to people who might not otherwise have voted," state Rep. Leah Landrum said after Internet voting ended Saturday. "This is something I know is going to stick around."

Vice President Al Gore defeated former New Jersey Sen. Bill Bradley by a nearly 4-to-1 margin in the Arizona Democratic primary, the nation's first binding election for public office using the Internet.

The voting was spread out across most of the week. From Tuesday through Friday, participants could cast their ballots by mail or from any computer where they could log onto the Internet, as long as they had obtained a personal identification number. Voters who waited until primary day had to go to a polling place to use a traditional paper ballot or, in most locations, a computer.

The primary drew some 78,000 ballots, doubling the previous record for turnout since the state party switched from a nominating convention to a primary in 1984. Just over half of the participants voted electronically.

Election.com, the company hired to run the primary, avoided any problems from hackers, even though a reporter from the online publication NationalJournal.com said he hired a computer expert to try to hack into the site.

Still, there were plenty of stumbles along the way.

Some voters didn't receive their personal identification numbers and had to call in to get them. Others ran into "system busy" messages or blank screens when they tried to link to the Web voting site, and some older Web browsers would not connect at all.

So many people flooded telephone help lines on the first day of voting that many got only busy signals.

State Party Chairman Mark Fleisher said election officials learned a lot from the experience.

"It's been real worth it," he said. "If you make democracy easy and put it in their living rooms, they will vote."

Many states watched the Arizona experiment. California, Oregon, Louisiana and others have been considering online voting.

But while many agree that Internet voting will become widely available, a California-sponsored study found hurdles the technology must overcome before it gains widespread use:

• Larger states need enough computer capacity for millions of voters -- far more than bogged down the Arizona vote at times.

• Until Internet access becomes as commonplace as television, election officials must guard against a "digital divide" between affluent people who have computers and the poor who don't.

• The system must be secure to protect the privacy of each vote and the integrity of the count. The bigger the target, the better the chance that a hacker will break in.

Those concerns are shared by the Voting Integrity Project, a Virginia group that unsuccessfully sued to block the Arizona vote.

The group's president, Deborah Phillips, said she worries other states will rush to join in without addressing such problems. "This election now gives blessing to Internet voting."

Phil Noble, president of PoliticsOnline, a South Carolina-based company that provides Internet tools for politics, said security and system capacity issues won't stand in the way for long.

And he noted that the push for Internet voting is coming from the public.

"Arizona in many ways was an Internet field of dreams," he said. "Build it and they will come. Well, they knocked down the gates to get to it."