TORONTO - Ontario Premier Dalton McGuinty says Ottawa will determine whether Canada's most populous province moves forward with nuclear power.

"The ball's in their court; they have to decide whether they want to sit down and talk to us," McGuinty said a day after it was revealed that the expansion of the Darlington nuclear power plant is now on hold because of cost concerns.

The Ontario government had been planning to spend $26 billion adding two new reactors at Darlington, on the shores of Lake Ontario east of Toronto, to meet the demands of a power-hungry province over the next 20 years.

But provincial officials are increasingly nervous about the future of one of the bidders on the project, Atomic Energy of Canada Ltd., a Crown corporation that's been at the centre of privatization speculation.

"We had a bidding process -- the AECL has emerged as the front-runner but not as the clear winner," McGuinty, on a two-day visit to the U.S. capital, said Tuesday.

"In order for that to happen we need a couple of things from the federal government -- we need some certainty about the future of AECL. Who are we going to be dealing with? The second thing we need is a better price."

Nuclear power is wildly expensive, McGuinty pointed out. The original Darlington nuclear station ended up costing almost $15 billion -- almost four times the initial estimate.

"There comes a point in time when nuclear becomes unaffordable, so what we want to do is ensure we get the best possible price for Ontarians. We want to know if (the federal government) is going to backstop AECL, and do they believe that it has a promising future for all Canadians? If they do, then we want to be part of that."

Ontario's energy minister, George Smitherman, said earlier this week that bids submitted for the project were too expensive, but added that just because the project is on hold doesn't mean the province has given up on nuclear energy.

France's Areva SA and Westinghouse Electric Co. also bid on the project.

McGuinty was in Washington to discuss Ontario's successes on the education front, but in a meeting with local business officials earlier Tuesday, he reported that the Obama administration's "Buy American" provisions were "all we talked about."

"There's a real concern and on my part there's a real disappointment," McGuinty said of the protectionist provisions in President Barack Obama's $787 billion economic stimulus package.

The measures have prevented Canadian businesses and manufacturers from bidding on American infrastructure projects that have received stimulus funding.

"This is out of synch with statements that have been made by the president as recently as last Friday, when he responded to the energy bill (and) said one more time: `We have to guard against protectionism,"' McGuinty said.

The United States should have learned its lessons from the 1930s, the premier added, when protectionist measures taken are thought to have contributed to the Great Depression.

"Now our world is even more inter-dependent and it's even more important to recognize that we're in this together, and in fact we got into this mess together, and the best way for us to get out of it is together."

McGuinty met Tuesday with Tim Pawlenty, the Republican governor of Minnesota. The governor informed him that 141,000 jobs in his state are tied to trade with Canada, as are 7.1 million jobs in the U.S. overall.

"We need to find a way to rise above the seductive political appeal of protectionism," McGuinty said.

"Intuitively what people believe is that: `Well, what we need to do is spend our own money on us,' but what experience has demonstrated again and again in recent years is that it's important for us to reach out and strengthen our global economy."