The SNP's wish to introduce a Local Income Tax (LIT) to replace the regressive and very unfair council tax is a great thing for Scotland, but potentially very good for the Lib Dems too.
A LIT has long been Lib Dem policy and if it works, and let's face it, it works in scores of other countries around the world so there is no reason to believe it won't work here, then it would prove the Lib Dems right in their support for the policy. But more than that, it will push the Tories and Labour in to a corner.
The Tories and Labour are going to have to defend the Council Tax, the last popular tax in the UK, to electors and themselves in order to oppose the SNP's plans.
In effect the Tories and Labour will form an alliance to defend the indefensible, and if the Lib Dems are right and campaign on this issue effectively, they can be made to be seen as backing the wrong horse.
The tag line "Remember The Labour Party/The Tory Party (delete as appropriate) voted to defend the unfair council tax this year and refused to support a fairer system based on people's ability to pay", might be a long line, but if repeated over and over again (and were I still writing Focus leaflets for Fakenham where I was a councillor I would be using this and recycling it every month), then it could prove very effective, especially if done in months when people's council tax bills land on their doorsteps.