SOME issues in the independence referendum have become so familiar - pensions, EU membership, the pound and defence - that a new debate is almost a light relief.
But this weekend's discussion at the Scottish Greens' conference, about the potential impact of a Yes vote on the environment, is important in its own right.
The emergence of the environment as a new frontline in the referendum campaign foregrounds the Greens and their radical vision, which goes well beyond the safety-first line of the SNP.
Co-convener Patrick Harvie claimed yesterday that this radical streak could make the Greens "crucial" to next year's result by converting the undecided to a Yes.
It is a big claim, but not ridiculous. The party attracted 4.4% of the vote in 2011, and 7.3% in the European election of 2009. In a tight contest, such numbers would matter.
Harvie says independence must be about doing things differently. And the Common Weal energy paper launched today at the Greens' conference speaks to that.
While Ed Miliband offers £2 a week off your electricity bill, this urges top-to-bottom reform of how electricity in Scotland is generated, distributed and sold, with the private sector displaced by the state and communities for the good of society.
Such ideas remind voters that the choice in 2014 is not like any other.
It is big, it is different, it is radical. Whether or not you agree with them, the Greens' ideas are welcome for bringing that point home.
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