Likely GOP presidential contender Tim Pawlenty announced Erik Helland’s hiring in a press release last week, noting that the two-term Iowa state legislator would head his Iowa staff.

The state House Majority Whip’s background includes a stint as a field staffer for John McCain’s 2008 presidential campaign. His background also includes a drunken driving arrest for which he appears to still be on probation.

The Polk County Attorney’s office confirmed Thursday that Helland pleaded guilty on Aug. 19, 2010, to one count of operating while intoxicated, first offense, and one count of interfering with official acts. Helland received a suspended sentence, which included three days in jail, 12 months of probation and a $1,250 fine.

He becomes the third staff member or prominent volunteer connected to Pawlenty’s campaign with legal problems related to alcohol. Two of them appear to be on criminal probation. One has resigned.

Republican consultants said that the unconnected issues do not so much question Pawlenty’s decision-making ability, but the string of incidents could develop into larger problem.

“I think it’s bad for the candidate and it’s a bad news story,” said one GOP campaign consultant. “I don’t think it’s a question of judgment. But it makes you the butt of a lot of late-night jokes … It’s not a trend you want as a candidate. It leads to not being taken seriously.”

Last month, Pawlenty selected eight activists to serve on his New Hampshire steering committee. One of them, former Nashua Alderman Dave MacLaughlin, is a convicted felon in Massachusetts, having been convicted three times for drunken driving. He served six months in jail and will be on probation until mid-July.

Pawlenty staffer Benjamin Foster resigned last month shortly after being arrested in Iowa for public intoxication and trespassing. He was allegedly drunk and returned home to the wrong house in early April. A 15-year-old girl found him trying to open the family’s back door.

The criminal history of campaign staff is often the subject of intense scrutiny before appointments are made. Asked about Helland’s past this week, a Pawlenty spokesman suggested that the arrest was common knowledge in Iowa, but declined say more.

But after Roll Call published news of MacLaughlin’s criminal history, the campaign offered this response:

“Dave MacLaughlin is a volunteer supporter of Governor Pawlenty and well-respected member of the Nashua community,” said Rich Killion, New Hampshire senior adviser for the Pawlenty for President Exploratory Committee. “Dave made terrible mistakes and has to live with those mistakes. The Governor supports Dave’s commitment to redemption.”

Foster’s arrest in Iowa embarrassed the Pawlenty campaign and inspired a rash of Internet jokes. Helland’s arrest, which occurred several months before he joined Pawlenty’s exploratory bid for president, was widely covered by Iowa media last summer and pops up as one of the top Google search results associated with Helland’s name.

The June 2010 incident was captured by a police dashboard camera. The video was obtained by local news media and posted on the Internet.

In the video, Helland initially refused to get out of his car.

“What do you mean, no?” the police officer asked Helland.

“I’m kind of a lawyer,” Helland replies.

“You’re not going to get out of your car?” the officer asks.

“I want to. I really do. I love you. I trust you. But I can’t, ‘cause it just doesn’t sound like a good idea.”