Trudeau says "No." He refuses to rule out participation by the other seven candidates.
The gentleman astronaut says he's ready for a debate between Trudeau and himself, anywhere, anytime.
His argument: a one-on-one debate would give liberal members and sympathizers a chance to better understand and compare the two men.
Trudeau replied on his blog that he wasn't going to exclude any of the other seven candidatesfrom taking part a debate: "I respect all the candidates in the leadership race. We will be in Halifax, Marc."
Trudeau added that he believes there will a chance for one-on-one exchange in Halifax on Saturday.
Garneau said Monday morning: "If he is actually qualified to become leader, he should have the courage of his convictions and display them in a face to face debate with me."
For three weeks Garneau has continually attacked Trudeau's political qualities. The vote is April 14.