A British newspaper that set off a trans-Atlantic political storm when it urged its readers to write to Ohio (search) voters in an attempt to sway their ballot choice in the U.S. presidential race said Sunday that it had ended the campaign.

The Guardian (search) newspaper said that it stopped giving out names and addresses of undecided voters after hackers broke into its Web site a week ago, effectively ending "Operation Clark County."

Editors also professed themselves overwhelmed with the response to the campaign — a response that included Guardian reporters being deluged with thousands of angry e-mails from Americans.

The newspaper also has abandoned plans to take four of the best letter writers to Springfield, Ohio, to meet voters. Instead it will send the winners to the "more tranquil" Washington, D.C., for a vacation.

The Guardian had invited its readers to contact voters in Clark County, Ohio, a swing state, about the importance of the Nov. 2 election.

The newspaper's Web site said letter-writers were free to support either President Bush (search) or Sen. John Kerry but noted that a Guardian poll showed 47 percent of Britons backed Kerry and 16 percent supported Bush.

Within the first day, more than 3,000 readers logged on to the newspaper's Web site to obtain the name and address of an unaffiliated voter taken from the electoral roll.

The campaign became a worldwide story, and Web site readers from several countries, including Australia, Japan, Canada, Morocco, Chile, France and Italy, applied for addresses.

A spokesman for the newspaper said Sunday that the project went well, with more than 14,000 addresses downloaded, when the site was hacked into last weekend "presumably by someone unhappy with the debate we had created."

The spokesman, speaking on condition of anonymity, said that the remaining addresses — about 20,000 — were downloaded by the hackers all at once and the newspaper decided to call it quits.

"It would have taken us several days to reconstitute the site, as we would have needed to repurchase the electoral roll, and as interest had already surpassed our expectations, and the competition element of the project was due to end within a very short period, we decided not to rebuild the site," the spokesman said.

Thousands of voters in Clark County still may receive letters from readers who managed to download the Americans' addresses before the hackers hit.

While the newspaper called its project a success, it created a headache for journalists at The Guardian, where media editor Ian Katz reported they received thousands of e-mails from angry U.S. voters, many of them staunch conservatives and some of them abusive.

"Hey England, Scotland and Wales, mind your own business," one American wrote in a letter published on the newspaper's Web site. "We don't need weenie-spined Limeys meddling in our presidential election."

In Ohio, an Oct. 15 headline in the Springfield News-Sun read: "Butt out Brits, voters say."

Katz, who dreamed up the project in a north London pub, said the campaign had been taken more seriously in some quarters than the newspaper had intended and rejected suggestions it could affect the outcome of the Nov. 2 vote in the county.

However, he said the outcry had led the newspaper to send its letter-writing prize winners to observe the final days of the election in Washington, rather than Springfield, where a Guardian delegation would be "bound to prolong the brouhaha, with unknowable consequences."

"I think I have an idea how Frankenstein felt," Katz wrote in a column on Friday. "Somewhere along the line, though, the good-humored spirit of the enterprise got lost in translation."