Orders of the Day - Let the Battle for Etobicoke Centre be joined!

After weeks of frantic speculation and preemptive spin, the much-anticipated Battle for Etobicoke Centre will take centre stage at a special summer hearing of the Supreme Court of Canada later this morning.

At stake: the Commons seat currently held by Conservative MP Ted Opitz, whose existential electoral status has been in limbo since May, when an Ontario judge declared the results of the 2011 general election null and void due to ballot irregularities, and handed an unexpected, if interim victory to Opitz' challenger, former Liberal MP Borys Wrznewskyj.

If the decision is upheld, the matter will go back to the voters of Etobicoke Centre, although the PM can wait up to six months to call a by-election. If it is overturned, well, that's that.

Follow CBC reporters @laura_payton and @LeslieMackinnon for all the latest updates.

Meanwhile, an ad hoc coalition of scientists, civil society leaders and "concerned Canadians" will mourn the "death of evidence," which they describes as a "casualty in the war on science", with a funeral service and procession to Parliament Hill. 

"In recent months," the advisory notes, "the role of Evidence in important public decisions affecting Canadians" has been "greatly diminished" by "unstaunched bloodletting at critical research programs in Environment Canada, Fisheries and Oceans Canada, the National Research Council of Canada, Statistics Canada and elsewhere ... the shutdown of irreplaceable systems vital to the health of Evidence, including the world-renowned Experimental Lakes Area, the Polar Environment Atmospheric Research Laboratory and the First Nations Statistical Institute" and,finally, "inadequate diet resulting from the loss of such important sources of information as the National Science Advisor, Law Commission of Canada, and National Round Table on Environment and Economy."

Among those scheduled to speak at the event:

• Dr. Jeff Hutchings, Professor of Biology at Dalhousie University and President of the Canadian Society for Ecology and Evolution
• Dr. Alex MacKenzie, a Pediatric scientist at the Children's Hospital of Eastern Ontario
• Diane Orihel, founder of the Coalition to Save ELA;
• Nathalie Des Rosiers, General Counsel for the Canadian Civil Liberties Association and former president of the Law Commission of Canada
• Maude Barlow, National Chairperson of The Council of Canadians

Opposition critics Anne Minh Thu Quach, Helene Leblanc and Ted Hsu are also expected to take part in the march. 

On the opposition leader circuit:

After spending the weekend gladhanding his way through the Calgary Stampede, Interim Liberal Leader Bob Rae heads to Fort McMurray, where he will take in the Athabasca oil sands -- including, the advisory notes, "Syncrude's mining and reclamation facilities" -- and visit a local air monitoring station before heading off to a roundtable with members of the Fort McKay First Nation and Metis Community.

NDP Leader Tom Mulcair, who is set to make his much-anticipated Stampede debut on Thursday, will spend today meeting with "community leaders" in Victoria.

Also out and about today:

• Defence Minister Peter MacKay delivers the topline announcement of the day at the Irving Shipyard in Halifax, where he is expected to highlight a "milestone" in the government's shipbuilding procurement strategy, after which it's off to New Glasgow for an infrastructure reveal.
• ACOA Minister Bernard Valcourt delivers federal funding to Edmunston-based Beaulieu Plumbing and Mechanical Inc., while elsewhere in New Brunswick, Robert Goguen hands out still more money to local businesses in Moncton and Dieppe.
• In Toronto, Minister of State for Sport Bal Gosal celebrates Pan Am/Para Pan Am Day in Nathan Phillips Square.
• International Trade Minister Ed Fast kicks off a "consultation" tour of Western Canada with a stop in Nanaimo, where he will expound on the need to "further deepen trade and investment ties throughout the Asia-Pacific region" before a handpicked audience of unnamed "stakeholders and key transportation and industry leaders"
• Finally, Transport Minister Denis Lebel joins his colleague Leona Aglukkaq for a "brief media availability" in Iqualuit. 

For up to the minute dispatches from the precinct and beyond, keep your eye on the Parliament Hill Ticker below -- or, alternatively, bookmark it and check back throughout the day.