At the end of the day, Philadelphia City Council President Darrell L. Clarke concluded that he already had what he wanted.

"I really enjoy the job I'm in. I enjoy the work we have been doing. I like my colleagues," he said Monday. "I saw no reason to leave at this point."

So, after months of Hamlet-like vacillation, Clarke announced that he would not run for mayor, but would instead seek reelection to Council.

Clarke's decision to not enter the 2015 Democratic mayoral primary may prove as fateful to its outcome as any other candidate's announced entry.

It provides a significant boon for State Sen. Anthony Hardy Williams, arguably the best-positioned African American in the race. It also opens the possibility that City Controller Alan Butkovitz might revisit his decision not to run.

"Let's be frank, Williams goes to the head of the pack with Clarke out," said Randall M. Miller, a historian and expert in local politics at St. Joseph's University. "If they can do cartwheels in the Williams campaign, they are doing them now."

Clarke's intentions had been the focus of attention for months, as he was wooed by key labor leaders and other political insiders, who saw him as a potential winner in a field that to this point has inspired little enthusiasm.

Clarke himself had encouraged the speculation, holding fund-raisers for the coming campaign season without identifying which office he might seek, and coyly telling reporters and others that a mayoral run was tempting.

In an interview Monday, Clarke said his indecision was sincere.

"I never was looking to be mayor," he said. "But people over the last several months expressed an interest in me. I mean, a lot of people. I was flattered. Based on the number of people and the type of people, I felt obligated to consider their request."

Despite the interest of others, Clarke said, he found that he did not have the burning desire needed to run for the office. "If you are going to run for mayor, you have to be all in," he said. "You can't half run for mayor."

Clarke said he was not yet prepared to endorse any candidate now in the race.

"Right now, my focus is on supporting my Council members and help them get reelected," he said.

Among Clarke's chief boosters has been John J. Dougherty, business manager of Local 98 of the International Brotherhood of Electrical Workers.

"I think that for the last few months, we understood this was going to be the case," Dougherty said. "Nobody was surprised. What it does is guarantee continuity in City Council. You will have a steady hand for whoever is the new mayor.

"There is nothing phony about Darrell Clarke," Dougherty added. "He is genuine. As I have always said, with Darrell around, there is always an adult in the room. There are no surprises with him."

There are three announced candidates - Williams, former District Attorney Lynne M. Abraham, and former City Solicitor Ken Trujillo. Former Common Pleas Court Judge Nelson Diaz has said he intends to formally enter the race this week. Former Philadelphia Gas Works spokesman Doug Oliver has said he will announce in February, as has former State Sen. T. Milton Street Sr.

In that field, Williams is the only African American candidate for mayor with significant experience, organizational support, and financial backing. He is running in a city where 52.7 percent of the registered voters are black. Historically, voters white and black have tended to cast their ballots along racial lines, although that pattern was much less pronounced in 2007, when Michael Nutter was elected mayor.

Oliver also is African American, but he has far less public-service experience and name recognition than Williams, son of the late State Sen. Hardy Williams, an icon in the black community. Street, while perhaps better known than Williams, is marginalized by his long and cartoonish career, which includes a stint in federal prison for tax evasion.

"This basically makes it a race of one black man vs. everyone else," Miller said. "If you had two strong black candidates, it would allow someone like Lynne Abraham to say to her base, I can do this. But with Clarke out, this has really changed the calculus."

Butkovitz had expected to be the recipient of the labor support that was courting Clarke. Butkovitz passed on the race in November, largely because Clarke's indecision had kept that support on the sidelines.

Reached Monday, Butkovitz said he was mulling his options.

"I have to take the pulse of the Philadelphia political community and figure out the lay of the land," he said.