Despite the efforts of some party leaders, the Democratic field in Minnesota’s Senate race seems to be anything but set more than a year ahead of the 2006 midterm elections.

The biggest unknown continues to be wealthy attorney Mike Ciresi.

Ciresi expressed his interest in the seat almost as soon as Sen. Mark Dayton (D-Minn.) announced his retirement in February. However, eight months later, he has yet to pull the trigger.

Most Minnesota political watchers believe Ciresi’s entrance is imminent but the longer he waits, the more time he gives Democratic frontrunners, Hennepin County Attorney Amy Klobuchar and child-safety advocate Patty Wetterling, to scoop up state convention delegates, volunteers and dollars.

“Amy Klobuchar and Patty Wetterling have been working the field since the beginning of the year,” said Minnesota Democratic Chairman Brian Melendez. “They’ve made a lot of progress. … Still the campaign is in its early days and clearly if Ciresi gets in, [he] changes the dynamics.”

Philanthropist Ford Bell also is seeking the Democratic nomination.

Most observers believe it is not “if” Ciresi gets in but “when.”

Sources said he is interviewing campaign staff and plans to make an announcement soon. Ciresi did not return calls for this story before press time.

Ciresi poured $5 million of his own money into the Democratic Senate primary in 2000 and captured 22 percent of the vote, which placed him second behind Dayton.

One Democratic source, who did not want to be named, said Ciresi can afford to wait because he is expected to spend liberally from his own pocket.

Ciresi’s law firm played a lead role in Minnesota’s lawsuit against the tobacco industry and reaped $427 million from the state’s $6.1 billion settlement.

Conventional wisdom holds that Ciresi benefits the most from wealthy real estate developer Kelly Doran’s recent departure from the Democratic race.

Doran had spent $750,000 of his own fortune on his Senate bid before changing course and deciding to run for governor next year instead.

Doran was the wild card in the race — a wealthy political novice with solid business credentials and savvy campaign help.

No sooner had Doran dropped out than EMILY’s List announced it was ditching Wetterling — whom the group had backed in last year’s 6th district House race — and endorsing Klobuchar.

While the decision was clearly a setback for Wetterling’s campaign, it may have been aimed more at Ciresi than Wetterling.

With Republicans solidly behind Rep. Mark Kennedy, Doran’s departure and Ciresi waiting in the wings, EMILY’s List decided “now is the time” to aid Klobuchar, President Ellen Malcolm said in an interview last week.

“We want her to have the momentum,” Malcolm said, adding that Ciresi might think twice about getting in if he sees that Klobuchar’s campaign is taking off.

“By every measure Amy Klobuchar is putting together a strong campaign,” Malcolm said. “She has more than half the state legislators [endorsing her], she has more than three times the money Patty has in the bank. She’s shown she can win a tough race … She really knows where she’s going, what she’s doing.”

Malcolm said the group, which backs female Democratic candidates who support abortion rights, does not want to lose the opportunity to add a woman to the Senate.

“We hope to avoid an expensive September primary so now is the time,” Malcolm said.

Both Wetterling and Klobuchar have said they will honor the state party’s endorsement — which will be decided at a June convention — and drop out if they do not win it.

In Minnesota, the major parties endorse candidates during summer conventions but those endorsements are not binding. Convention losers can choose to go on to a party primary, which is held in September.

“The conventional wisdom is Ciresi will drag it to a primary,” the Democratic source said.

In 2000 Dayton entered the race late, skipped the party convention, won the primary and ultimately spent $12 million on his race.

For her part, Wetterling was not fazed by EMILY’s List’s decision to back Klobuchar.

“We have a lot of respect for the organization but they have been very vocal about trying to get Patty to run in the 6th Congressional district,” said Carol Butler, Wetterling’s spokeswoman. “Patty believes she is the candidate with the best chance of beating Mark Kennedy and keeping the seat in the hands of the DFL [Democratic-Farm-Labor Party].”

According to the Politics in Minnesota newsletter, Wetterling has polled party delegates and found that 70 percent are still undecided. Of the 30 percent who have committed to a candidate, they are split equally between Wetterling and Klobuchar.

The state party and the Democratic Senatorial Campaign Committee say they are not taking sides, though both would prefer to have the matter settled at the June convention.

“It’s a very strong field,” DSCC spokesman Phil Singer said. “We’re lucky to have so many strong candidates in that field in Minnesota.”

Melendez said the state party will focus on attacking Kennedy while the endorsement process works itself out.

“It’s our job to keep in the news the failings of Mark Kennedy and his campaign so the candidates can focus on a more positive message to voters.”