From ABC7

SAN FRANCISCO (KGO) -- For many, Mike Hennessey is the only San Francisco sheriff they've ever known, but after more than three decades on the job, he's decided not to run again. So the race to replace him is on. The top three candidates held a debate on Friday.

One is a sitting member of the board of supervisors, one is a captain in the sheriff's department, and the third a retired undersheriff who once led the police union. They're vying to replace the longest serving sheriff in San Francisco's history -- Hennessey, who's retiring after 31 years on the job.

"...Whom I believe is probably the most innovative sheriff not just in California, but the United States -- Sheriff Mike Hennessey and he's endorsed me to succeed him," said San Francisco Supervisor Ross Mirkarimi.

Though only Mirkarimi has Hennessey's endorsement, the other two were quick to insist they're also on his good side.

"I worked as Mike Hennessey's undersheriff. Mike Hennessey recruited me to be his undersheriff because he knew the career I had," said Chris Cunnie a former undersheriff and union leader.

Cunnie's endorsed by both the San Francisco Chronicle and the examiner. Capt. Paul Miyamoto's endorsed by the unions representing the sheriff's rank and file.

"I think the best person to continue the sheriff's legacy of success is someone who's been a part of that success," said Miyamoto.

Issue number one in the campaign is what to do when the state sends hundreds of inmates from its crowded prisons back to the six county jails that the San Francisco sheriff oversees. The state calls it realignment.

"We have the tools in place to be adequately prepared to deal with this challenge," said Miyamoto.

Miyamoto is optimistic; Mirkarimi not so much.

"The state has failed in its ability to rehabilitate prisoners. So they are now deflecting that responsibility back to local government," said Mirkarimi.

Cunnie wants to deflect it right back to the state by asking for money.

"We have to be in Sacramento, we have to make sure the governor does something long term on the ballot to fund realignment," said Cunnie. On legalizing marijuana, he says no. "I don't believe that we want to send a message to young people that smoking marijuana is a good thing. And if you legalize it that's the message."

Miyamoto says now's not the time.

"It would take a massive undertaking and a lot of money and resources to do that effectively," said Miyamoto.

Mirkarimi says legalize it and save money.

"Governments have absolutely wasted billions of dollars in the war on drugs," said Mirkarimi.

Throughout the hour-long debate just about the only thing that all three candidates consistently agreed on is that Sheriff Hennessey's trademark cowboy boots will be awfully big ones to fill.