Travis Tazelaar, campaign manager for the effort to approve the Dream Act, which would let some illegal immigrants pay in-state college tuition rates, said his group hasn't used robocalls and has no plans to.

"I think they're a pretty poor way of communicating, especially considering how much people don't like them," he said.

Both sides in the fight over Question 7, which would expand gambling in Maryland, have made use of robocalling. The opposition, financed by Penn National Gaming, did not answer questions about who has recorded on their behalf. Discloure reports show the campaign has spent about $1.3 million on what it calls "outbound phone operations" — a category that could include such calls.

Supporters, financed largely by MGM Resorts International, reported spending at least $50,000 on what they explicitly labeled as robocalls. The campaign committee provided recordings of robocalls by such stars as Longoria, Copperfield and boxer Oscar de la Hoya.

"Question 7 means millions of dollars for Maryland's schools through expanded gaming," Longoria tells voters.

Ann Beegle, a former Maryland Democratic Party executive director and political consultant, said she's seen reaction to those calls on Facebook.

"From the men, it's been very positive. If that's [the] target audience, that was effective," she said.

Brad Chism, president of Washington-based Zata3 Consulting, said he's putting two kids through college on the strength of his robocalling business. However, he said, the calls have to be used the right way.

"They're useful in communicating a late-breaking piece of news, responding to political attacks, for generating attendance at events," he said.

One thing they aren't good for, he said, is stimulating turnout.

"In terms of getting infrequent voters to change behavior and go to the polls, robocalls have very little impact," he said.

Robocalls, of course, have a checkered history in Maryland politics. In 2010, robocalls made by the campaign of Republican former Gov. Robert L. Ehrlich Jr. gave African-American voters — presumed to be O'Malley supporters — false assurances that the election was over and they could stay home. That incident led to the convictions of former Ehrlich campaign manager Paul Schurick and consultant Julius Henson on criminal charges.

Chism said his firm played a small part in that drama. He said that when O'Malley backers learned of the calls, they had his firm record an instant response in which U.S. Rep. Donna F. Edwards, the 4th District Democrat, refuted the message before the polls closed.

"These things don't cost a lot of money, and they're easy to use, and they get overused and ... they're used by thugs from time to time. And that doesn't help the electoral process," Chism said.