The moderator of Thursday鈥檚 federal leaders鈥 debate says he was struck by how respectful the leaders were towards one another during the event.

Speaking to CTV鈥檚 Power Play on Friday, Paul Wells spoke about the dealings that occurred as each leader spoke, and moment the cameras did not catch.

鈥淭here was a lot of off-camera negotiating among the moderator -- me -- and the other three leaders while one of them was talking,鈥 said Wells. 鈥淚f Harper was talking and I pointed to Elizabeth May, the others would typically let May speak next.鈥

Going into the debate, Wells said he expected the other leaders to gang up on NDP Leader Tom Mulcair, who was leading in the polls when the election was called last weekend. But he says that didn鈥檛 happen, leaving Mulcair to hold his own through the two-hour debate.

鈥淗e had to do his own work. He had to make his own case and I think that lessened the amount of bump that he might expect to get out of this debate,鈥 said Wells.

Surprised by separatism

Wells said he was also surprised by the prominence of Quebec separatism talks in Thursday night鈥檚 federal leaders鈥 debate, spurred by Liberal Leader Justin Trudeau.

鈥淚 was floored that it came up in a debate in the current electoral context. And that had everything to do with Justin Trudeau needing to distinguish himself from (NDP Leader) Thomas Mulcair to his advantage,鈥 said Wells. 鈥淚鈥檇 be really surprised if this came up during the French language debate later on in the campaign.鈥

In the democratic institutions portion of the debate, Trudeau attacked Mulcair for trying to undermine the Clarity Act, which says a vote of 50 per cent plus one is not enough in a sovereignty referendum. Mulcair bit back, saying he has fought against separatism his whole political life.

The exchange led to one of the highlights of the evening, with Mulcair repeatedly pressing Trudeau to say what he thinks is an acceptable percentage for the 鈥測es鈥 side to win in a Quebec sovereignty referendum.

"You want a number, Mr. Mulcair?鈥 said Trudeau. 鈥淚'll give you a number. Nine. My number is nine. Nine supreme court justices said one vote is not enough to break up this country and yet that is Mr. Mulcair's position.鈥

Harper stayed relatively quiet during the exchange, accusing Mulcair of 鈥渢rying to throw gasoline on a fire that isn鈥檛 even burning.鈥

鈥淎 useful debate鈥

Wells admitted the debate was a bit 鈥渨eird,鈥 due to the fact that it was new format and the inexperience of Mulcair and Trudeau at the federal debate level. But he said the timing of the event kept everyone more 鈥渃hill,鈥 as the debate was so early in the election campaign.

Overall though, Wells was satisfied with the evening.

鈥淎gainst all odds, me making up how to do a debate kind of as I went along, and some of the participants really leery of this whole experience, I think we produced a useful debate.鈥