BETTER late than never.

This is the week when the pro-Union campaign began to take shape. First came the launch of the cross-party devo plus campaign to counter the SNP's devo max. There were debates in Glasgow and Edinburgh in which the many voices of civic Scotland were heard and those for and against independence went head to head. And yesterday the independence referendum was again the focus when Labour and the Liberal Democrats assembled in Dundee and Inverness for their spring conferences.

One question that plagues the counter-campaign to the SNP concerns leadership. By common consent there is no-one of Alex Salmond's level of recognition or popularity to take him on one to one. All the more reason to avoid a gladiatorial-style contest, especially as the opposition encompasses such a wide range of views. There are many different ways of saying no to independence. That is why in The Herald today ex-LibDem leader Charles Kennedy puts himself forward as "a" rather than "the" figurehead for the emerging pro-Union campaign. In 1983 he was the Baby of the House, having been elected to the Commons for his vast far-flung constituency at the tender age of 24. That means that nearly three decades on, and following a career and personal life that have spanned various vicissitudes, he counts as an elder statesman, despite being still in his early 50s.

He brings not only his vast political experience but also a Highland perspective to the campaign, a perspective from which Edinburgh sometimes looks as distant as Westminster. If the Unionists parties are to take the fight to the SNP, the other parties too must wheel out big hitters, such as Alistair Darling and Annabel Goldie.

Also, as Mr Kennedy argues, Labour and LibDems need to put aside their antipathy to sharing platforms with the Tories. (That is an interesting perspective from the most prominent LibDem to be lukewarm about the prospects of coalition with the Conservatives.) Otherwise the SNP will profit from playing divide and rule.

There are three major challenges for the Unionist parties. First, they need to find a way of uniting under one umbrella, even if their arguments for keeping the United Kingdom together rest on different premises. Many disparate pro-Union campaigns will play into the hands of the independence lobby.

Secondly, they need to run an upbeat campaign. Last May Labour paid dearly for its reliance on scare tactics. Yesterday Alex Salmond labelled opposition to the SNP and its ambitions as "mired in negativity". Every poll emphasises the numbers of Scots who remain agnostic about the benefits of independence. If they are to win the argument, the Unionist parties must not only challenge the SNP on the specifics of independence but also put a persuasive case for the benefits of life inside the UK. As Mr Kennedy observes, ultimately it is a contest that rests on "gut instinct" rather than constitutional minutiae.

Thirdly, Labour, LibDems and the Tories need to challenge the SNP more effectively on their record in government. Despite holding the balance of power at Holyrood since 2007, the SNP are past masters at taking the credit for feel-good news, while blaming others – the Coalition, Labour, Brussels, the weather – for any bad news. That is partly because of the distinct shortage of what commentators call "big beasts" on the opposition benches at Holyrood. Too many of their best and brightest preferred the bright lights of Westminster. Now, if there is to be an even-handed debate on the future of Scotland, some of them must show leadership. Win or lose, Charles Kennedy's is an important voice in this crucial contest for Scotland's future.