After four months of relative calm, the level of intrigue in Georgia’s open-seat Senate race intensified last week, as a wealthy Republican businessman tossed his hat in the ring and a freshman House Democrat indicated that he is also thinking about doing so.

In an interview Friday, former Godfather’s Pizza Inc. CEO Herman Cain said he is laying the foundation to campaign for the seat of retiring Sen. Zell Miller (D), making him the third Republican to enter the race.

Rep. Johnny Isakson (R) — who announced in January — lost his status as the lone candidate two weeks ago, when Rep. Mac Collins (R) said definitively that he is mounting a bid for Senate next year.

While no Democrat is currently running for the seat, a spokesman for Rep. Jim Marshall (D) confirmed that the freshman Congressman had been approached about the race and that he is entertaining the idea of jumping in.

“He’s interested,” said Marshall spokesman Doug Moore. “Who wouldn’t be?”

Although sources said Marshall has talked with Democratic Senatorial Campaign Committee officials about the race, Moore said he was “not at liberty to talk about any of the people who have approached us” about running.

Moore added that Marshall had the “ideal profile for a Democrat to win in Georgia,” noting his background as a decorated Vietnam War veteran and the geographical importance of his base in middle Georgia.

In his first few months in office Marshall has compiled a moderate voting record, and last week he was one of just seven House Democrats to vote for final passage of President Bush’s tax-cut package.

Marshall won his swing 3rd district seat in 2002 by just more than 1,500 votes in a race against former Bibb County Commissioner Calder Clay (R), who has announced he is running again.

The freshman’s potential Senate bid was the topic du jour among Republicans at the state GOP Convention in Macon two weekends ago, according to sources who attended the event.

Republicans believe Marshall may be looking at the Senate race because he faces a tough rematch in a presidential election year. Moore, however, said Marshall’s re-election prospects would not be a factor in his decision, for which he has no official timetable.

“He knows anything he runs for … it’s going to be a tough race,” Moore said.

Aside from Marshall, state Attorney General Thurbert Baker (D) is considered one of the Democrats’ few remaining top-tier prospects after two other statewide officials indicated they have no interest in the race.

On the Republican side, Cain was in town last week to meet with officials at the National Republican Senatorial Committee and members of the Georgia delegation. He said he has already filed a statement of candidacy, formed an exploratory committee and begun raising money for the race, although he declined to disclose the amount he has so far. On Friday he was in the final stages of hiring a campaign manager.

“I assure you I am dead serious about this,” Cain said, after noting that some people have questioned the legitimacy of his candidacy. “I’m not a person to toy with things.”

Cain said he will spend the summer fundraising and gathering support with the goal being to launch a full-scale campaign after Labor Day. He also would not rule out dipping into his personal resources for the race.

“I’m not showing that card at the present time,” he said when asked about the possibility of self-funding.

Cain became president of Godfather’s Pizza in 1986, and in 1988 he successfully leveraged a buyout of the company from Pillsbury. He served as president and CEO for a decade and in the 1980s was one of only two black CEOs of major companies nationwide.

Cain, 57, is now a professional motivational speaker and CEO and president of T.H.E. Inc., which stands for The Hermanator Experience. The company promotes his keynote speeches, the three books he has written about leadership and self-empowerment, and his inspirational tapes and gospel music CD.

“I acknowledge it will be an uphill battle,” he said, referring to the Senate race. “I acknowledge that I have not come out of years and years of party involvement or political involvement. … But that’s one of the greatest things about this country … is that just because it’s an uphill battle doesn’t mean that you can’t win that battle.”

While he has never been a candidate for political office before, Cain has actively supported Republican candidates and causes in the past.

In the past two election cycles, Federal Election Commission records show, he has given more than $23,000 to Republican candidates and committees. In the same time period he also contributed $17,500 to the PAC of the National Restaurant Association, an organization that he once served as president and CEO.

In the 1990s he served on the Economic Growth and Tax Reform Commission, established by then-Speaker Newt Gingrich (R-Ga.) and then-Senate Majority Leader Bob Dole (R-Kan.).

In 1996 he served as a senior adviser to Dole’s presidential campaign and in 2000 he supported the presidential primary campaign of millionaire flat-tax proponent Steve Forbes (R).

Cain describes himself as a conservative Republican. Last year, he contributed $1,000 to the campaign of former state Rep. Bob Irvin (R), who ran to the right of then-Rep. and now-Sen. Saxby Chambliss (Ga.) in the GOP Senate primary.

“I am a conservative Republican by most of the labels you want to put on a conservative Republican,” he said.

On the surface, Cain’s candidacy would appear to help Isakson in a three-way race. Collins is already being billed as the conservative alternative to Isakson, although the two lawmakers primarily differ only on the issue of abortion. Therefore Collins and Cain, who also opposes abortion rights, could end up splitting the conservative base vote in the primary.

However, Cain may also have to contend with some accusations that he is a carpetbagger. While he was born and raised in Atlanta and graduated from Morehouse College there, in 1986 he moved to Omaha, Neb., where Godfather’s is headquartered. While his executive assistant is still based in Omaha, Cain said he moved back to Georgia about three years ago.

Meanwhile, at least one other Republican who has been contemplating whether to get in the race indicated last week he is content to watch the other candidates from the sidelines.

“I’ll probably just let them” run, said Rep. Jack Kingston (R-Ga.).