THE Coalition command paper Scotland in the United Kingdom, which was published last week to deliver the pre-referendum vow on greater devolution, had a nicely ironic subtitle.

It was, apparently, "an enduring settlement".

It did not endure long, with the Scottish Government quick to demand the removal of all clauses which would give Westminster a veto over decisions Holyrood had expected to make itself.

But, as the document says, these are "draft" clauses, not tablets of stone.

"The coming months will see work to further refine the clauses," it notes in the Next Steps section.

When, after the general election, the clauses are gathered in a new Scotland Bill, as with any legislation there will be scope to modify and improve them.

This is not just convenient Unionist patter, but the message from the Campaign for Scottish Home Rule today.

Its nationwide consultation on Home Rule regards the Smith proposals as "only the beginning".

It is also the message from the SNP in the general election campaign, when they argue a large group of MPs could extract more powers beyond Smith.

Modifying the Scotland Bill already in prospect would be the obvious route to achieving that.

So while it is right to highlight shortcomings in the current draft clauses, it would be wrong to despair of them as an insoluble stitch-up.

Politics is a fluid business, and pressure can bring change - particularly at election time.

The ballot box is the next step for Smith.

However the command paper ducked a fundamental question - when will the new powers be delivered?

The precedent is far from encouraging.

The last major round of devolution began with the Calman Commission, established in December 2007.

Its modest proposals on tax, air guns and drink drive limits became the 2012 Scotland Act.

Some changes are in place, but the principal advance, the setting of a distinct Scottish Rate of Income Tax, will not begin until April 2016.

Last week, politicians rightly complained about the long-delayed Chilcot Inquiry report on Iraq.

But the Calman process, despite its smallness of ambition, has outlasted Chilcot: more than eight years from end to end, against Chilcot's six.

The Smith process so far has moved quickly, but there is a long parliamentary road ahead.

The pressure that must now be applied to improve the clauses must be equalled by a determination not to let the process succumb to yet more sloth.