No government can be long secure without a formidable opposition.

- Benjamin Disraeli, 1804-1881

On March 24, the federal New Democratic Party will choose Canada's new Leader of the Opposition - and potentially the country's next prime minister.

One of eight contenders will take the torch from Jack Layton, who became the NDP's first-ever opposition leader after the 2011 election before tragically dying from cancer.

I've met the leading candidates privately in the past few months to get a sense of what drives them before deciding whom to endorse.

Three candidates are perceived to be the top tier: Montreal MP Thomas Mulcair, Toronto MP Peggy Nash and former NDP president Brian Topp of Toronto.

Topp was twice Layton's national election campaign director and has the support of former NDP leader Ed Broadbent and ex-Saskatchewan premier Roy Romanow.

He has the strength to be self-deprecating while making it seem like you are being let in on big secrets, becoming a confidante even over coffee at Tim Horton's.

Raised in Quebec but having worked for years in Saskatchewan politics and Ontario labour, Topp brings together all the elements one could imagine for NDP success.

But then, so do Mulcair and Nash.

I first met Mulcair at lunch with Layton in 2007 - and was extremely impressed, as I was again last month.

Firm without a hint of overconfidence, politely disagreeing without rancour and with a polished style, he makes a very strong and memorable connection.

A former provincial cabinet minister, Mulcair led the NDP breakthrough in Quebec.

Nash, who was the Canadian Auto Workers union's senior negotiator and the first woman to lead bargaining with the auto industry in North America, is tough all round and never gives up.

After losing a close 2004 election, she won in 2006, lost in 2008 and won again in 2011.

In person, Nash is poised, a skilful listener and a diplomat - all traits found in the best negotiators.

No one can possibly replace Layton - but each believes they can succeed their late leader's biggest project of all - to not just become the opposition but to form a social democratic Canadian government.

In future, I'll discuss the considerable abilities of the other NDP leadership candidates in B.C. MP Nathan Cullen, Ottawa MP Paul Dewar, Manitoba MP Niki Ashton, Quebec MP Romeo Saganash and Nova Scotia businessman Martin Singh.

Read more at www.TheTyee.ca and http://billtieleman.blogspot.com/ Email: weststar@telus.net