UPDATE: Dalton McGuinty's Liberals have won their third consecutive election. Whether they will form a minority or majority government remains to be seen. See the below scenarios to see what might come next.
Ontario's political make-up could look very different after millions of voters cast their ballots Thursday.
If the Liberals are re-elected but don't have the seat count needed to form a majority government will they strike a deal with the NDP to stay in power despite ruling the option out during the campaign?
Could the party that obtains the most seats be shut out from government?
Here's what the constitutional experts and political scientists believe may happen:
1. Liberal Majority (More than 54 Liberal seats)
No change. Premier Dalton McGuinty would likely re-shuffle his cabinet with the strength he has left and any new talent the Liberals pick up on Oct. 6
2. Strong Liberal Minority
McGuinty could try to govern without making a formal deal by reaching across the aisle to obtain support from both opposition parties on different policy areas. For example, the Liberal could collaborate with the NDP on health care and with the Tories on tax cuts. Prime Minister Stephen Harper governed from 2006 until March 2011 by seeking the support of at least one opposition party and by betting his opponents wanted another election less than he did.
If the Liberals obtain anything higher than 47 seats, Jason Roy, an assistant professor in the department of political science at Wilfred Laurier University, argues the parties would be better served co-operating through an informal agreement.
"If they (the Liberals) are coming in at the low-50s, high 40s, I think it hurts them or can potentially hurt them to enter in any formal agreement," Roy told The Huffington Post Canada. "Nothing would be signed. There would be no piece of paper that could be held up, two years from now (during a potential election), to say: 'Hey, you folks went into the coalition.' "
3. Weak Liberal Minority
Liberals play let's make a deal in order to guarantee themselves a certain time in office free from votes that would threaten the fall of their government and likely plunge the province into another election campaign.
"If (the Liberals) are five seats away from the majority, I don't think they will have anything to do with a coalition. But if they are significantly below a majority, I think, they would consider it," Ned Franks, an emeritus professor in the department of political studies at Queen's University, said.
Franks argues the NDP would be better off insisting on a power-sharing deal, with seats at the cabinet table, rather than a loose arrangement with the Liberals.
"I think (the NDP) would go with coalition because they got stung pretty hard in the Peterson government with Rae as a supporter but not a rainmaker," Franks said about the 1985 Accord inked by then-NDP leader Bob Rae and Liberal leader David Peterson that saw a number of NDP priorities put into law in exchange for the party propping up the minority Liberals for two years.
"They could demand portfolios they care about, like health and education," he said of Andrea Horwath's team.
But would Ontario voters accept it?
"We've had coalitions before and coalition isn't a dirty word," Franks notes. "(Prime Minister Stephen) Harper made it so, but it is not a dirty word."
If the Liberals win a weak minority, Jonathan Malloy, an associate Political Science professor at Carleton University, believes "some pretty serious negotiations would start happening as early as this weekend."
"But it may take a while to reach a bargain," he cautions.
4. Tory Minority
a) It is quite possible that if Tim Hudak's Progressive Conservative Party wins the most seats on Thursday, the Liberals and NDP could still form a government.
McGuinty, as the incumbent, remains premier even if he loses the election, according to constitutional convention. He is within his rights to visit Ontario's Lieutenant Governor David Onley and tell him that he plans to seek the confidence of the legislature to govern, Franks said.
"There is no constitutional principle that says that the party with the most seats forms government, the principle is the party that enjoys the confidence of the house forms the government," Franks said.
b) Hudak could also reach out to the NDP to try to make a deal, although party differences suggests a marriage between the left and the right may be untenable.
"The NDP and the Conservative party are more ideologically apart, it will be harder for them to make a bargain. Whereas the NDP and Liberals are obviously more adjacent so it will be easier for them to bargain," Malloy said.
Still, he notes that in 1985 there were talks between the NDP and the Conservatives.
"So it might happen again here, but on balance you'd have to say that it is unlikely," Malloy added.
Last year, the U.K.'s coalition government cemented a relationship between unlikely bedfellows. After a May vote which resulted in a hung Parliament with no party having an absolute majority, the Conservatives formed a coalition government with the Liberal Democrats giving them five cabinet seats. Polls show, however, that the left-leaning Lib Dems have plummeted in support as they have propped up unpopular Tory policies such as a raising the cap on tuition fees.
5. Tory Majority
Hudak is ecstatic and celebrates.
6. NDP Majority
Horwath is ecstatic and celebrates.
7. NDP Minority
Horwath reaches across the aisle and tries to make a deal with the Liberals or the PCs. The reverse of scenarios 2 or 3 or 4b.
As Roy suggests, "Anything is possible."
Join The Huffington Post Canada team as we liveblog the Ontario election results starting 8 p.m. ET.