Maricopa County Sheriff Joe Arpaio has been raising fistfuls of money for months now, but the question is: for what?

If Arpaio knows what office he will run for next, he isn't saying yet. But he promises to let voters know by May 1 whether he will hang onto his sheriff's badge or toss his hat into the ring for governor.

Arpaio has raised $2 million to date, money he cannot touch until he starts campaigning for sheriff or shifts gears to run for governor. He has been soliciting contributions for nearly a year, and the response has been striking even for someone with his name recognition.

Despite - or maybe because of - state and federal investigations into Arpaio's office, donors have handed over $25 and $30 contributions in droves.

If Arpaio makes a bid for governor, he could roll that $2 million into the statewide campaign, experts say. Arizona statutes allow for candidates to transfer funds to another campaign when seeking a different office, as long as the legal-contribution limits are equal or greater for the new office.

Arpaio will not be able to use the money to mount a legal defense against what he describes as various left-leaning enemies, but a politician seemingly playing a martyr is usually an effective strategy to get donations, said Bruce Merrill, an Arizona State University professor who conducts the Cronkite/Eight poll.

Merrill noted that Arpaio seemed to pick up supporters after demonstrators interrupted a question-and-answer session with the sheriff at Arizona State University last year.

"The more they rail against Joe, the more it helps him. He ought to give money to those demonstrators," Merrill said. "The media covers that, and what's the message? Here's a guy who's getting pounded on because he's tough on criminals."

Arpaio could use the money he has raised so far to campaign against a recall election if someone attempts to force one. That is what political strategists had in mind when they started sending out solicitations last year, said Chad Willems, Arpaio's political consultant.

"These left-wing groups and their allies in the media need to know just how strong the support is among law-abiding people like you for me and my policies," one of Arpaio's solicitation letters reads. "They are mounting an all-out effort to remove me as Sheriff, including the latest talk of a recall campaign."

Arpaio has such fundraising potential among a certain segment of conservative voters that other groups have used Arpaio's name to raise money, too.

A border-protection group recently promised supporters a copy of Arpaio's book in exchange for donations. Another group claimed to be raising money to help Arpaio fight the American Civil Liberties Union, Willems said.

Neither is affiliated with Arpaio, but Willems said there is little Arpaio can do to stop organizations from trading on his name.

"It has nothing to do with us - we don't trade lists with those people, we don't have any interactions with those people - it's like a free-speech thing," Willems said. "There's always going to be people trading on different people's names."

The prospect of Arpaio possibly running for governor has generated the most interest - and at least some campaign revenue. Willems said the campaign returns donations with any mention of "governor" included.

However, people not affiliated with the campaign have sent out mass e-mails and posted information on the Internet with claims that Arpaio is running for governor. Those missives advertise a post-office box where supporters can contribute to the campaign - the same address where Arpaio collects his 2012 campaign donations.

Willems said those solicitations have not generated a huge response.

The campaign occasionally receives checks with a note attached indicating the donation is for Arpaio's illegal-immigration-enforcement efforts.

"We just have to send it back and say, 'If you want to support the sheriff's re-election, here's a form,' " Willems said. "We vet all that stuff."

A potential gubernatorial run by the 77-year-old sheriff has political observers curious about how Arpaio's tough-on-crime, short-on-politics stance would play at the statewide level.

There is consensus that he would be a tough competitor in the GOP primary, which already has a crowded field of four official candidates. What is less certain is whether Arpaio could parlay his popularity among conservative voters into a general-election victory.

"He's always done pretty good in Maricopa County, but I don't know how that translates," said Bruce Hernandez, research director at the Behavior Research Center, a Phoenix polling firm. "People seemed to have a pretty high opinion of him for so many years running the sheriff's office, but I don't know that that translates to running the state."

At a Young Republicans event last month in Mesa, Arpaio told the crowd he would "lead the state with my personality," if elected governor, and that he would leave detailed decisions to experts. "I can hire someone to give me a position paper on education," he said.