MPs in the House of Commons are tackling a terrorism bill in a debate infused with a new sense of urgency following the Boston Marathon bombings one week ago.

Though Bill S-7 has been in the works for roughly a year, the Conservatives are making a new push to pass the legislation quickly in the wake of the recent disaster which killed three and wounded more than 180.

Highlights of the measures included in the Combating Terrorism Act include:

  • Making it an offence to leave the country to participate in acts of terror
  • Granting police the powers to pre-emptively arrest someone and hold them for up to three days without charge
  • Imprisonment for up to 12 months if an individual refuses to testify before a judge in an investigative hearing

The debate also follows revelations that four young men from London, Ont., were radicalized and that at least two of them were killed in the gas plant siege in Algeria early this year. One of them is currently serving a two-year prison term in Mauritania.

Monday was to have been a Liberal opposition day in Ottawa, during which newly-minted Liberal Leader Justin Trudeau planned to come to the defence of Conservative backbenchers who say they are being muzzled, restricted from speaking in the Commons unless their topic is approved by the party whip.

Trudeau planned to introduce a motion Monday that would strip party whips of their ability to control who speaks in the House of Commons.

But just hours after Trudeau announced his plans, Government House Leader Peter Van Loan made a change to the Commons schedule. The S-7 debate was moved to Monday, and the Liberal opposition day moved to Wednesday, giving Harper more time to smooth-over some MPs' ruffled feathers.

After Trudeau complained about the last-minute change, the Conservatives suggested he was playing politics with a national safety issue.

"Grits bleating because oppo day moved back 2 days so House can pass the 'Combating Terrorism Act'. Seriously," tweeted Harper spokesperson Andrew MacDougall.

In his comments Sunday, Public Safety Minister Vic Toews denied any suggestion the government is preying on fears stoked by the Boston bombings as leverage to pressure the opposition to pass the bill.

"This is something that we've been needing to do for quite a while," he said on CTV’s Question Period on Sunday. "The incident in Boston simply demonstrates the need for this type of legislation."

The minister said that there have been calls for a proactive approach to preventing people from travelling overseas to become radicalized and militarily trained in terrorist organizations.

"I think there's a widespread consensus in our society that Canada has an international, and not just a national obligation to prevent these individuals from involving themselves in this type of activity," he said.

The New Democrats have indicated they will not support Bill S-7, saying the Conservatives should instead focus on restoring slashed funding for border security.

Liberal MP Francis Scarpaleggia said the Liberals will be supporting the legislation and noted that many of the original measures were first introduced by the Chretien government in 2001.

"We've been supporting it all the way through before the incident in Boston ever occurred," he said. "This particular piece of legislation is not about budgets, it's about bringing back some legal measures to help in the fight against terrorism."