TORONTO - The race for Toronto's next mayor is shaping up to be a showdown between two political foes who once battled it out in the Ontario legislature.

George Smitherman -- Premier Dalton McGuinty's right-hand man and top enforcer -- dropped out of cabinet Monday to pursue a bid to be mayor, potentially pitting him against former Progressive Conservative leader John Tory.

Tory, a wealthy and well-connected political operative for former prime ministers Brian Mulroney and Kim Campbell, is mulling another shot at the city's top job after losing to David Miller in 2003.

Smitherman, who had been serving as energy and infrastructure minister, said he's taking the leap because his hometown needs him, not because he couldn't see a way to move up from being McGuinty's No. 2 man.

"Had I chose to remain, I think I have a very good future here," Smitherman said, adding that he's been given "extraordinary opportunities" in both the health and energy portfolios.

"But my city calls out. My city shows that it has a need to restore a sense of power to the office. And I think that I have the skills -- a combination of experience, passion, energy and roots in the city that make me well-suited to this challenge."

McGuinty, who vowed for weeks that Smitherman was staying put, shrugged off his departure as well as pointed questions about why a second cabinet star has run out the door in last few months.

His "Jedi mind trick" failed to work on one of his staunchest allies, the premier joked.

"I've got a great team of people and they're all equally committed to public services here in the legislature, but nobody signs on for life," he said.

"And from time to time, it's only part of the natural order of things that people pursue other opportunities."

According to the Queen's Park rumour mill, that could include Municipal Affairs and Housing Minister Jim Watson -- who some say may take a run at Ottawa mayor -- and veteran Windsor Liberal Sandra Pupatello, who is currently serving as minister of economic development and trade.

Michael Bryant, who harboured hopes of succeeding McGuinty as premier, stepped down in June after a decade in politics.

There's speculation that recent tension between Smitherman and some of his cabinet colleagues pushed him to take the leap that he's mused about since September.

A government source acknowledged that Smitherman, rather than the wind-power deal he was touting, became the target of some "hostility" at a recent cabinet meeting. But Smitherman denied it was a factor in his decision to leave.

It was a "difficult choice," Smitherman, 45, acknowledged.

"It called out to my heart and to my mind (and) said, 'Toronto is a place where you should seek to bring your energy to the fore,"' he said. "And that's the path that I'm following."

Part of the appeal may be that local politics tends to be more of a one-man show driven by personal influence and political capital, while provincial politics is dominated by the party dogma of discipline and cabinet solidarity, said Bryan Evans, a politics professor with Toronto's Ryerson University.

"I can understand the allure of being the mayor in a fairly significant centre like Toronto, Ottawa, or even Hamilton and London, just because you're in a position to arguably have a bit more political control," he said.

But Tory could prove to be a challenge. A recent poll suggested that about half of decided voters would vote for Tory, with Smitherman coming a distant second with about 20 per cent support.

Tory declined to comment Monday on whether he'd throw his hat in the race, saying only that he's still giving it "serious consideration."

Instead, he invited his would-be rival on his afternoon talk radio show, which Smitherman accepted.

The ball is now in Tory's court to decide if he wants to run against him, Smitherman said.

But Smitherman will likely have to deal with the political baggage of the eHealth scandal and his attack-dog reputation, which some say won't play well at city hall.

He also may find himself sparring with Tory over the untendered contracts at eHealth, which Tory was largely responsible for bringing to light when he was the leader of the Opposition Tories.

The fiasco over electronic health records culminated in an auditor's report that found a lack of government oversight allowed consultants to run amok as the province spent $1 billion over 10 years with little to show for it.

David Caplan, who took over the health portfolio from Smitherman, resigned over the scandal, prompting accusations that he fell on his sword to preserve his more powerful colleague's political ambitions.

Smitherman is the last thing Toronto needs, said Progressive Conservative Peter Shurman.

"The Minister of Scandal? I don't think so," he said. "He's just evaporated as far as provincial politics are concerned."

Smitherman is only gunning for mayor so he can escape the scandals he's helped create at Queen's Park, Shurman said.

"He can say whatever he wants, the bottom line is they threw David Caplan under a bus for his responsibility on eHealth and he was responsible for 22 per cent of the time during which a billion dollars of taxpayers money was thrown away," he added.

"George Smitherman was responsible for the other 78 per cent, and you can't go be mayor of Toronto without answering for your previous sins."

Experts say Smitherman may have difficulty in convincing voters that he's a leader who can rise above the fray, given his aggressive style to date.

"He's trying to say he's the person in the middle, he's trying to create this view that he can be above the more stronger ideological factions but the problem is we assume he's going to go up against John Tory, who gives that impression even more strongly," said Henry Jacek, a politics professor at Hamilton's McMaster University.

Smitherman said he will keep his Toronto seat for the time being, and make a formal bid for mayor closer to the March 1 deadline.

Liberal veteran Gerry Phillips, who held the energy portfolio before Smitherman, has assumed those responsibilities again until the end of the legislative session.

Smitherman appears to have already attracted a fan club within the Liberal caucus, including Labour Minister Peter Fonseca, as well as Toronto colleagues Eric Hoskins, Tony Ruprecht and Laura Albanese, who all showed their support by attending his news conference.

McGuinty said he won't stop others from going, leaving open the possibility of more cabinet exits.

Unlike those who traded in their political credentials for a well-paid seat at a corporate boardroom table, Smitherman still wants to serve the public, just in a different arena, McGuinty said.

"I regret losing him," the premier added. "He was a real driver for me, there's no doubt about that, but I think he's going to make a powerful contribution in whatever avenue of public service he now pursues."