How appropriate that they held the unveilings at the Canadian War Museum.

Before this Battle for LeBreton Flats is over, there may well be a call for a non-proliferation treaty regarding over-the-top promises.

A year and half ago, the National Capital Commission, which is in charge of all federal lands and such buildings as Rideau Hall and 24 Sussex Dr., called for proposals on what might be done with more than 20 hectares of abandoned and toxic land opposite the war museum and within sight of Parliament Hill. It was expected that four proposals would be tabled, but two dropped out late in 2015, leaving a pitch by the Ottawa Senators and a few partners to put up a new hockey rink, and a second proposal by Montreal-and-area developers to erect a new … hockey rink.

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The NCC had been looking for a legacy project, something that would, in the words Tuesday of CEO Mark Kristmanson, create "a district of national significance."

In their attempts to make it "more than a hockey rink," then, both sides pulled out all the stops – one group unleashing its imagination rather more than the other.

The group fronted by Ottawa Senators owner Eugene Melnyk had always let it be known that a new arena would be at the core of its proposal. Although the team plays out of the perfectly fine, 20-year-old Canadian Tire Centre in Kanata, fans have complained from the beginning about the distance and the traffic. A downtown rink would attract more fans, particularly from the Quebec side of the Ottawa River, and with a light-rail train service being built right through LeBreton Flats, would be better situated for other events, such as concerts.

The plan would also include a new Ottawa public library, an Abilities Centre that would be accessible to all, a Canada House to provide short- and long-term subsidized accommodation for military families and, of course, hotels, restaurants, retail and a variety of housing. "We want to bring 7,000 people who used to live here back to the city," architect Barry Hobin said.

The second bid came from an entity called Devcore Canderel DLS Group and includes two influential Montreal billionaires, Andre Desmarais of Power Corp. and Guy Laliberte, founder of the internationally renowned Cirque du Soleil. It also boasts William Sinclair, co-founder of Ottawa-based JDS Uniphase and the Mierins family, owners of eight car dealerships in the area, as well as Ogilvie Realty.

They call their proposal "Canadensis: LeBreton Re-imagined," and clearly imagination was given free reign. The project would include a bandshell, several large squares for retail and art, a science and innovation pavilion, a planetarium, a beer "Breuseum," a skatepark, a Ripley's Aquarium, a new central library, a YMCA, the "World Automotive Experience" museum, and the Canadian Communication Centre which will act as a sort of museum for broadcasters and reporters, which seems rather apt considering the media job losses of the past couple of weeks. Perhaps, given its close proximity to Parliament Hill, they could call it the "Memorial to the Victims of Journalism."

Resources, however, remains a huge and unanswered question, as neither side was allowed by NCC to put a price tag on its plans. Some in the Senators group, however, have said their project would cost roughly $3.5-billion, including a $600-million arena; presumably the Canadensis plan would run considerably higher. The NCC believes it impossible this early to give fair cost estimates, as there are too many matters to work out first, including the cost of cleaning up this land that has been abused for nearly two centuries by mill operations and factories. The Senators group has estimated the cost of cleanup alone at $170-million.

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Both sides say they will first purchase the land from the NCC, and the NCC says it is legally committed to seek market value for property it sells. Both sides say their projects can be privately funded with no public funds required, but Canadians are justifiably suspicious and have examples, from Montreal's Olympic Stadium to Toronto's SkyDome, where early promises grew into public outrage.

An equally intriguing issue is the matter of a team to play in the new rink, whoever builds it. If the Senators' project gets the go-ahead, they hope to have a new rink ready for play by the 2020-21 National Hockey League season. The Canadensis group, obviously, has no NHL team, leading many to suggest this could be a sports equivalent of a "hostile takeover," with Mr. Melnyk forced to either sell his team to them or else strike some arrangement.

Asked if he would ever sell his team, Mr. Melnyk said, "No." Asked if there was any way an arrangement might be reached whereby he would allow his team to play in the other group's rink, Mr. Melnyk answered, "No."

Let the fighting begin.