THE referendum is still a dozen weeks away but the Scottish Government has taken the step of proposing an "interim constitution" - the document which would come into force from independence day in 2016 until a permanent Scottish Constitution is written.

Ministers want a broad, participative process to give everyone in Scotland to chance to help shape the Constitution.

That's a very welcome aim, and there are many international examples we can draw from about how to gain maximum public involvement.

But there's a danger in waiting until 2016.

I'd far rather we began that public involvement as soon as the referendum is over.

If it's a Yes vote (and the polls are heading that way) it seems likely that it will be thanks to a high turnout, with many people voting for the first time in years, or even decades.

It'll be important that we don't lose that energy and positivity in the period between the referendum and independence itself.

And just because the "interim constitution" is meant to be temporary is no reason to expect that we just sign up on sight.

The SNP must show a willingness to listen to the public, and to other political parties, in shaping it.

As for the content, there are good points and bad. It has a strong commitment to human rights and equality, to nuclear disarmament and to the principle that the people are sovereign.

But it contains no mechanism for the accountability at the highest level - the Head of State.

Whether you want to keep the Queen or elect our own Head of State, it's important that the role is clearly defined and the person carrying it out is accountable.

More importantly, the "interim constitution" is in fact not really a constitution at all.

That's understandable, since before independence nobody will have the legal authority to create one.

But it's more properly understood as a "Basic Law", a piece of constitutional legislation which would be passed by a simple majority at Holyrood and could be amended in the same way.

The SNP's mandate in government comes from their hugely successful 2011 election win.

But that was an election to the devolved Scottish Parliament; it doesn't give a mandate to write a constitution.

It will also be a four year old mandate by the time this legislation is debated. It would be wrong for them to think they could pass this foundation for independence, this Basic Law, with their slender one-seat majority in that context.

An interim constitution is clearly necessary, and there's a lot to welcome in this draft. But the Government must accept the responsibility to reach a high bar on this crucial issue. That must mean a two-thirds majority.