The British Parliament has begun a daylong debate over whether to grant the government authority to conduct airstrikes against ISIS in Syria.
The U.K. is already conducting strikes against ISIS in Iraq.
Prime Minister David Cameron, pushing the motion at the start of today's 10-hour debate in the House of Commons, suggested the U.K. faces a choice between going after "terrorists in their heartlands," or waiting for them to come to Britain, The Associated Press reports.
Such strikes wouldn't make Britain more likely to be targeted ... because, Cameron said, Britain was already in "the top tier of countries on the [ISIS] target list."
The motion has the support of Cameron's Conservative Party, as well as the Democratic Unionists and the Liberal Democrats, according to the BBC.
NPR's Peter Kenyon reports that the issue "has divided the opposition Labour Party, whose leader, Jeremy Corbyn, opposes airstrikes in Syria — as do thousands of people who gathered to demonstrate outside Parliament." The Scottish National Party members of Parliament are also opposed to expanded airstrikes.
But Peter notes that "support for joining the air campaign against ISIS in Syria as well as Irag is growing, and the government sounds confident about being able to order the strikes to begin in a matter of days."
Rhetoric over the motion has been running hot. British media reported that Cameron called opponents "a bunch of terrorist sympathizers" on Tuesday, prompting calls for an apology at the start of Wednesday's debate.
Corbyn, meanwhile, has characterized the motion as "an ill-thought-out rush to war."
In 2013, Cameron advocated legislation that would have opened the door to U.K. military action against Syrian President Bashar Assad's regime to deter the use of chemical weapons. It was rejected, a blow to the prime minister's authority.
This time around, Peter reports, Cameron is confident he'll gain the support of a majority of Parliament.
The vote is expected around 10 p.m. local time, or 5 p.m. ET.