THE launch of the Yes campaign for independence on Friday marks the official beginning of a debate which could change our country forever.

It is a debate which will be joined by the No Campaign when it is launched next month and which will continue until the referendum, which is expected to take place in October 2014.

With so much at stake it is to be expected that the debate will at times become heated. Heat is not what Scotland needs. It is essential that over the months ahead the debate is given room to breathe and that every voter can find their place in it.

There should be no place for personal abuse and hate-filled attacks.

Independence is an issue which transcends strict party lines, and so Scotland needs a debate that rises above the dismal tribalism of recent years. This presents challenges for both sides.

The Yes Scotland campaign needs to be aware that the online behaviour of a minority of its supporters can seem bullying and intimidating.

Some treat the mildest criticism, or even questioning, of the SNP's policies or leader as a declarations of war.

Immune to argument, they attack the unwary without pity or reason, and do their cause no favour: they are antithetical to an informed debate.

Having a view on the monarchy, monetary union, an oil fund, or the viability of a Scottish defence force post-independence which doesn't mirror the SNP's doesn't automatically make someone a Unionist stooge or in thrall to the Labour party.

These issues are too important and nuanced to have debate on them snuffed out by online abuse.

With its emphasis on Obama-style online campaigning, Yes Scotland should do what it can to let debate flourish free from such interference.

The No campaign has its own uphill challenge – it has to say something positive about the Union.

We say it's a challenge not because we believe necessarily that there is nothing positive to say on the Union, but because so far the No campaign has been as unremittingly negative in its comments as the Cybernats.

The No campaigners promise positivity, but they have made such promises before to little obvious effect. After pumping out one scare story after another, perhaps they can no longer tell the difference. Or perhaps they think rubbishing independence by definition makes a positive case for the Union.

It doesn't.

Scotland isn't just being asked whether it wants to dissolve a 300-year marriage, it is also being asked whether it wants to reaffirm the relationship, maybe for another 300 years.

To secure a commitment as big as that, the Union has to put something on the table. It has to argue its corner and offer Scots some positive reasons for not making a break.

A mantra of "safety first" isn't enough.

So starting now, and for the next two-and-a-half years, the onus on the No campaign will be to articulate a positive message which informs the debate and presents real choices to voters.

Not the Home Office saying an independent Scotland would be catnip for terrorists, or suggestions that Scots would no longer be able to travel to England, or Treasury crystal-ball gazing about an economy sliding into the sea.

This is a debate for grown ups.

As to the Sunday Herald's position, we are among those the SNP calls 'the persuadables', open to argument but not as yet totally convinced.

At past elections we have supported Alex Salmond for First Minister, because like many voters we saw the alternatives and shuddered.

We believe that since coming to power, his Government has done well, and deserves credit.

But, also like many voters, our support does not translate directly into backing for independence. It is too big a decision for a snap call.

We absolutely believe an independent Scotland could run its own affairs, sustain a viable economy, and rub along fine with the other nations of the world.

But that does not make us blind to the benefits of Union in a time of acute financial crisis, or indifferent to our social and historic bonds.

The UK may be an unusual arrangement for four countries, but it isn't necessarily a wrong one.

Along with our readers, we will make our mind up when the time comes on the basis of which camp puts forward the most convincing and inspiring arguments.

But we will be doing our bit for the debate too. In print, online and at special events, we promise to expand the breathing space we all need.