Justin Trudeau has the backing of almost two-thirds of his fellow Liberal MPs in the race to be leader of the federal party.

Twenty-one MPs have hitched their wagons to Trudeau, and three are supporting Marc Garneau. The other six leadership candidates haven't been endorsed by any MPs.

Several MPs are remaining neutral or haven't yet made up their minds.

Supporting a future leader, and doing the legwork of fundraising and getting out the vote for the candidate, can pay off in critic's positions, or, if the leader becomes prime minister, a parliamentary secretary or cabinet seat.

MPs supporting Trudeau:

• Scott Andrews
• Gerry Byrne
• Scott Simms
• Wayne Easter
• Lawrence MacAuley
• Sean Casey
• Dominic Leblanc
• Rodger Cuzner
• Mark Eyking
• Geoff Regan
• Massimo Pacetti
• Lise St-Denis
• John McCallum
• Kirsty Duncan
• Frank Valeriote
• Kevin Lamoureux
• Ralph Goodale
• Hedy Fry
• Mauril Bélanger
• Judy Sgro
• Scott Brison

MPs supporting Marc Garneau

• Ted Hsu
• Jim Karygiannis
• John McKay

MPs remaining neutral or undecided:

• Francis Scarpallegia (as one of the heads of the Liberal Rules Committee, he can't take sides)
• Stephane Dion (as former leader he says he's remaining neutral)
• Carolyn Bennett (as Chair of the Women’s Caucus, she prefers to stay neutral)
• David McGuinty (not supporting anyone)
• Denis Coderre (remaining neutral)
• Irwin Cotler (remaining neutral)
• Bob Rae (interim leader, can't support anyone)
• Judy Foote (staying neutral because she is Liberal Whip)

MPs can sign up supporters

Of course, candidates with the most MP support don't necessarily win.

Marc Garneau has three MPs supporting him for leader of the Liberal Party, to be decided April 14. (John Woods, Canadian Press)

That's because the Liberals have opened up the contest to allow literally anyone, as long as he or she is not a member of another political party, to vote for the contestants. In doing so, a new category of voters was born called supporters.

But MPs, with their contacts and on-the-ground intelligence about their ridings, can be valuable allies who can beat the bushes for supporters.

And since each riding is worth 100 points — to ensure that small PEI ridings, for instance, have as much weight as large Toronto ones — if you’re a candidate, it can't hurt to have the local MP mining the riding for you.

Winnipeg North MP Kevin Lamoureux says he's signed up 3000 supporters for Trudeau. Avalon MP Scott Andrews tweeted that as of Janurary 8 he has signed up 1200 Trudeau supporters in his Newfoundland riding. Cardigan MP Lawrence MacAuley says he's signed up 500, again on behalf of Trudeau, in his PEI riding, but adds it's a small district.

In an interview, Lamoureux said he's been in ten elections, federally and provincially, and he's never seen a phenomenon like Trudeau. "People want to have their pictures taken with him," he said. "At the end of the day, it's good for me."

Etobicoke North MP Kirsty Duncan, who is Trudeau's seat-mate in the House of Commons, told CBC, "I'm tired about politics being about polls....and politics, " she said, her voice rising. "It's supposed to be about people, it is, and in politics you so often meet someone who shakes your hand, and looks for the most important, the more important person in the room. Justin makes every person feel like they're the most important."

Duncan said that in the long marathon voting nights in Parliament, she and Trudeau talked about policy, everything from "dementia to climate change." She noted that since he's been in Ottawa, Trudeau has spent his time criss-crossing the country trying to get to know Canadians.

"No-one should ever sell my friend short," she added.

Justin Trudeau has attracted the most support of Liberal MPs. (John Woods, Canadian Press)

Kingston MP Ted Hsu said he's attracted to Marc Garneau for "three things: intelligence, integrity and discipline." And, he added, for Garneau's executive experience because he headed the Canadian Space Agency. Tsu thinks the Liberal party badly needs to be reorganized and that Garneau is the leader who could make that happen.

Although Tsu said he would throw his full support behind Trudeau if he wins, he also said, "I wonder if it's simply enough to look at the polls and see that Justin could put us in the lead. Is that really going to happen, or is there some really hard organizational work to be done?"