Independence is necessary to give Scotland a more prosperous economy along with a just society, First Minister Alex Salmond will insist.
In his keynote address to the Scottish National Party annual conference in Perth on Saturday afternoon, Mr Salmond will argue that leaving the rest of the UK is not solely a "constitutional objective". Instead he will claim it is about the possibilities that independence offers.
Scots will vote on whether or not the country should become independent in a referendum in two years' time. At the start of this week Mr Salmond signed a deal on how the crucial ballot should be staged with Prime Minister David Cameron.
On Saturday, the SNP leader will tell delegates: "Our cause is not and never has been just about a constitutional objective. It is about using the powers of an independent Scotland to create a more prosperous economy and a more just society."
With the referendum due to take place in 2014, Mr Salmond and his SNP have two years to try to persuade Scots to vote in favour of leaving the UK.
But a poll published on Thursday - the first day of the party's conference - showed support for the union was almost double that for independence.
In the Ipsos Mori survey 30% of those questioned backed Scotland becoming independent, compared to 58% who supported the union, while 12% were undecided. Another poll suggested only half the people who support independence are strongly in favour of it.
A YouGov survey, commissioned by the pro-union campaign group Better Together, found 31% were in favour of independence, with 16% of people strongly supporting this and 15% who "tend to support it".
In his speech, Mr Salmond will argue achieving a Yes vote in the referendum is necessary to secure and build on key achievements of the devolved Scottish Parliament since 1999, including the introduction of free personal care for the elderly, free prescriptions for all and the abolition of university tuition fees for Scots studying in the country's universities.
He will also contrast the opportunities Nationalists believe independence can bring with the austerity programme being implemented by the UK Government.