Dr Alasdair McDonnell's Press conference on Tuesday fired the starting pistol in the SDLP leadership race. Nominations don't close for a fortnight, but it looks unlikely any more candidates will join McDonnell and Margaret Ritchie, the Social Development Minister, in the contest.

It's not exactly a glittering field. In political parlance, neither is 'a big beast'.

It's the first time in the party's 39-year history that there has been a leadership election and the stark truth facing the party is that, if the person elected plays his or her cards wrong, it could also be the party's last leadership election.

The party has been bleeding votes for a decade, a loss which became a haemorrhage in 2004 when the party dropped 100,000 votes in the European election.

Next year's general election is another critical test. The SDLP must hold its three Westminster seats.

The immediate task for a new leader is therefore clear: to restore organisation and morale and stem the flow of votes.

Organisation and finance are areas regarded as Alasdair McDonnell's forte. A successful businessman himself, he is also a formidable motivator, but a polarising figure in the SDLP.

He and Mark Durkan did not gel as leader and deputy leader. McDonnell was not allowed a free hand in organising as he had hoped and allowed his frustration to show.

The good doctor can be ruthless and forceful and does not suffer fools. For some in the party his elevation to deputy leader was a shock and the same people now fear for their future if he were to become leader.

You could see some of McDonnell's opponents lined up behind Margaret Ritchie as she declared her candidature.

One is Carmel Hanna, MLA from McDonnell's own South Belfast constituency. Another is Alex Attwood from West Belfast.

For many people in the party Margaret Ritchie is the 'Stop McDonnell' candidate. For every member who believes McDonnell is exactly what is needed to shake the party up, blow fresh air through it, there's a member who would be horrified if he became leader, fearing that he's too brusque, volatile and unpredictable. It looks like a tight race which could turn pointed.

Margaret Ritchie hopes to garner support among the party's strongest areas: South Down and Foyle where the biggest branches are. Ritchie's popularity in the SDLP has soared after her dogged stance against money potentially going to fund groups connected to loyalist paramilitaries. Being attacked by Peter Robinson didn't do her any harm either. However, while Alasdair McDonnell could never be criticised for lack of ambition and drive, Margaret Ritchie has always been content to remain in the shadow of Eddie McGrady, working for decades in his constituency office and unhesitatingly accepting his decision to stand again for Westminster, both in 2005 and again next year at the age of 75.

She is the safe, establishment candidate. She will rock no boats. She threatens no one in the SDLP.

The same can't be said for McDonnell who believes some people in the SDLP need threatened. He's a firm believer that in political parties hot air rises and dead wood floats and that, if there isn't change, the SDLP will submerge under the weight of that dead wood.

Where will he get his support if Ritchie holds on to the big branches?

First, his own constituency. Although his running mate, Carmel Hanna, supports Ritchie, McDonnell still rules the roost there. Other parts of Belfast are not important because there are no SDLP members in large swathes of the city.

However, long before he declared his hand, McDonnell has been canvassing individual SDLP members across the North and it's reckoned he has already spoken personally to at least half the potential delegates to the election in February. This was the method he used in his successful bid for deputy leader.

Will it pay off again? MLAs have a vote, but there are only 16 of them compared to about 400 party delegates and that's where McDonnell is concentrating his fire.

The technicalities of the election aside, the new leader faces serious problems, the first of which is the average age of party members and elected representatives. The SDLP seems to have frozen about 25 years ago, around the time of the Anglo-Irish Agreement.

Incredibly, Mark Durkan - the outgoing leader at 49 - is their youngest MLA. Margaret Ritchie is 51 and Alasdair McDonnell 60.

Compare David Cameron (43) or Brian Cowen (49). There's something wrong with a party whose current leader is its youngest MLA.

There are no visible young figures in the party. Yes, they do have a few young councillors, but none has developed a political profile. None is an obvious candidate for stardom.

Finally, policy. What does the SDLP want now that the Good Friday Agreement has been achieved?

They exude an attitude of entitlement and bitterness, forgetting that voters don't care about past achievements.

The leading figures spend their time attacking Sinn Fein's policies. When John Hume was leader everyone knew what the SDLP wanted. They were sick hearing him repeating it. What does the new SDLP leader want? Can either McDonnell or Ritchie enunciate a separate identity for the SDLP, look to the future, carve out a path to follow that will not only enthuse members but attract new young recruits?

Failing that, this leadership election will be the last.