Expect lots of debate in the fall session of the House of Commons. (Adrian Wyld/Canadian Press)

MPs are vowing to be civil as they return to Ottawa on Monday for the fall session of Parliament, but hot-button issues like the fate of the gun registry and the handling of migrant ships could easily derail promises of peace.

"I don't expect it's going to be a bed of roses, I don't expect there will always be agreement, but we certainly are committed to make it work," Conservative House leader John Baird pledged Thursday, minutes before accusing Liberal Leader Michael Ignatieff and NDP Leader Jack Layton of being "Toronto elites" for supporting the federal long-gun registry.

The CBC's Louise Elliott, who has covered Parliament since 2002, said Baird's quick change of tone on Thursday is just a hint of what's to come this fall. She expects clashes, especially between two newly appointed House leaders — and known scrappers — Baird and Liberal David McGuinty.

"I think we know this is going to be a tense and sometimes aggressive session," Elliott predicted. "Every time we have a new session or a new sitting, there are promises of civility, and that usually lasts about 15 minutes."

The first issue MPs will likely clash on is the gun registry. On Wednesday, MPs will vote on a Liberal motion to defeat a Conservative backbencher's bill to repeal the long-gun registry.

Liberal House leader David McGuinty, left, and Conservative House leader John Baird are expected to clash as the fall session of Parliament resumes on Monday. (Canadian Press)

With the Liberals and the Bloc Québécois poised to vote to halt Tory MP Candice Hoeppner's private member's bill and the Conservatives set to support the bill, the fate of the registry lies with the NDP, which allows its MPs to vote however they want on private member's bills.

Layton has indicated he has enough votes to save the registry, but Baird says the issue is not a done deal.

"We aren't conceding defeat yet, before Wednesday," Baird said Thursday. "We'll see who shows up and we'll see whether they're going to listen to their constituents [who want the registry scrapped] or whether they're going to listen to Mr. Ignatieff and their friends in Toronto."

Prime Minister Stephen Harper's Conservatives are, however, trying to figure out a Plan B in case Hoeppner's bill is killed, CBC News has learned. The party could introduce another private member's bill, but this would be difficult since House rules state that the House can only make one decision on a matter in a single session. It can't re-examine the same issue twice.

Prisoner pensions, migrant ships

Other issues expected to be hot this fall are the economy, job creation and crime. Several pieces of legislation were introduced in the last session that will need further debate — bills dealing with issues such organized crime, RCMP reform, and the protection of sexual assault victims.

Prime Minister Stephen Harper has faced management problems this summer, pundits say. (Adrian Wyld/Canadian Press)

MPs are also in the process of considering a bill to strip retirement benefits from serial killer Clifford Olson and hundreds of other federal inmates, and they're debating a bill that would see the House of Commons grow by 30 seats, with Ontario, Alberta and British Columbia standing to make all the gains.

On Sunday, the Conservatives announced plans to expand allowances for wounded soldiers, boosting monthly payments to the most severely injured.

But one of the first issues expected to be tackled this fall will be the handling of migrant ships. The Conservative government has been floating the idea of new laws since a ship carrying 492 Tamil migrants arrived in B.C. on Aug. 12. The Conservatives have said they are considering ways to increase penalties against those convicted of human smuggling and bar ships from entering Canadian territorial waters.

"The government is looking at a comprehensive response to the threat of people-smuggling operations," Immigration Minister Jason Kenney said last week. "You have to stay tuned for those details."

While MPs consider various pieces of legislation, pundits say the Conservatives will have to shake what has been a bit of a rocky summer and gain back strength going into the fall. The party has come under attack for G20 summit spending, proposed changes to the census, fighter jet purchases and a willingness to fund sports arenas that would serve professional teams.

Tom Flanagan, Harper's former chief of staff, said the events of the summer speak to a management problem that Harper has not faced before. The Harper Flanagan remembers working with, for example, would not have tolerated his own MPs sporting Nordiques jerseys to show their support for a new arena in Quebec City that could see the re-emergence of the defunct NHL team.

"Now you've got Quebec MPs, including cabinet ministers, publicly trying to pressure the prime minister," he said. "This is simply astounding in terms of the history of the running of Conservative parties. I think it's more evidence of the breakdown of the management of the party over the summer."