Duffy housing flap now threatens Wallin

Controversy over Mike Duffy's Senate housing allowance has mushroomed into a bigger question, whether he's entitled to sit in the Senate at all, that now threatens to ensnare colleague Pamela Wallin.

For the past week, Duffy has been caught up in a controversy that began with questions about potential abuse of the housing allowance and has since grown into a broader constitutional quandary that could soon include his fellow former broadcaster.

The Constitution requires senators to be resident in the provinces they're appointed to represent, but what constitutes residency is not explicitly spelled out.

The Senate's internal economy committee announced Friday that it is seeking legal advice as to whether Duffy, who owns a home in Ottawa, is actually resident in Prince Edward Island, where he owns a cottage.

Committee chairman David Tkachuk said Duffy spends more than 60 days a year in P.E.I., but whether that's sufficient to satisfy the residency requirement is unclear.

"I always thought it was pretty simple, but when you talk to lawyers you find out how complex this really is," Tkachuk said in an interview.

Wallin's name got dragged into the mix Friday by New Democrats in the House of Commons.