Good evening! This week's edition of the In Common newsletter comes from Common Weal board member Isobel Lindsay, who was in charge of developing campaigns for the SNP in the 1970s and 1980s.

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WHAT is the SNP's Westminster story? To get through to voters in the trash bin of UK politics you need a unique selling point (USP).

What can the SNP offer in its current situation, which to be very diplomatic we could describe as one of full-spectrum problems?

One big advantage – but certainly not sufficient on its own – is the weakness of its opponents.

Labour leader Keir Starmer is a man totally devoid of political principles and ethical standards. These are not the same thing. You can have strong values but have no integrity in pursuing them or you can have few substantive principles but still abide by fair standards of institutional behaviour. Starmer has neither.

He jumped with remarkable speed from being an apparently loyal Jeremy Corbyn shadow minister to the far-right of the Labour Party.

But even more damning has been the ruthless suppression of what remained of the Labour left, no matter how dirty the tactics. Scottish voters have little respect or regard for him.

And what is there to say about Rishi Sunak? A shallow chancer, intelligent but with no substance. Scottish voters also know this. But voters don't in general have high expectations of political leaders, so this won’t be the decider.

While these negative points are easy, the SNP's opponents also have easy targets.

Scandals and Holyrood policy weaknesses are not the fabrication of opponents. They are real.

You can make some plausible excuses about limitations of power, but mostly, honesty is best.

Appearing to reject what was a not unreasonable sanctions package for unacceptable behaviour of an MSP at the start of the election campaign was an incomprehensible error of judgment, but candidates will have to live with it.

But voters want change and the SNP has to convince Scottish voters that in the Westminster context they are a necessary part of that change. There is no point in trying to produce twenty reasons in a six-week campaign, but it needs to produce three big reasons why their Westminster presence really matters.

Getting rid of all the Tory MPs is not one of them. If your priority is only to get rid of a small number of Scots Tories, you might as well vote Labour. You need to have a real positive case for your Westminster presence.

There will be other pro-independence parties standing – Alba and Greens. They may have better policy positions, but in a first-past-the-post election, they will not win. Only the two existing MPs standing for Alba might have an outside chance.

A Westminster independence presence will depend on the performance of the SNP. So, what are those unique selling points which no other parties can offer the voters?

There is no other party that can prioritise Scottish interests if they do not coincide with those of the UK majority. Scottish Labour or Conservative MPs will not be allowed even to challenge their Government, never mind vote against them.

That is not a theoretical issue. Shadow chancellor Rachel Reeves has announced that Labour's plan is for big infrastructure projects to be financed by private capital (back to Private Finance Initiatives?) and shadow health secretary Wes Streeting plans to expand the use of private health providers in the NHS in England.

What will the implications of this – and the further public austerity that is coming – be for Scotland?

The SNP needs to project itself as the independent voice for Scotland in Westminster as well as the voice of Scottish independence. There is no one else in the London Parliament who can or will be that voice.

It has been Westminster's shame that the SNP group has been the only party that has given voice to large sections of the UK public on crucial international issues.

On Gaza, where there has been a clear UK majority opposed to Israel's appalling war crimes, neither Labour nor Tory have acted for that majority.

For Scotland, the only Westminster opposition to the nuclear weapons that have turned our Clyde into the top target in western Europe has been the SNP. Labour rebels have been silenced.

So, the message should be that only the SNP group at Westminster represent millions of Scots on international issues, including relationships with Europe.

Most voters may not put these at the top of their priority list but that does not mean that they do not have strong emotional feelings about them. Millions of Scots will be completely disenfranchised on major international issues without a substantial SNP Westminster group.

Around half of Scottish voters support independence. Without SNP representation at Westminster, half of all Scottish voters will have no one there to represent their aspirations.

Summing all of these USPs up on its own probably does not represent the strong, independence-first campaign some were hoping for. Nor does it inspire with fresh ideas or new talent.

But it can arrest the decline in the SNP vote – and may help to turn it around.