OVER the past couple of weeks, a number of senior figures within the SNP have aired the idea that the next independence referendum should be delayed until after the 2021 Scottish election. The argument is that SNP should fight that election campaign on a renewed mandate for a referendum, and that the return of a pro-independence majority to Holyrood would provide a solid response to the cries of the British nationalist parties that Scotland doesn’t want another vote. It’s an argument some of us in the independence movement who are not in the SNP don’t find very convincing.

The SNP already have a mandate for another independence referendum, a mandate which has been validated on no fewer than three occasions. Scotland voted for a pro-independence majority in Holyrood at the last Scottish elections. The mandate sought by the SNP in 2016 was for the right to hold another independence referendum should there be a change in material circumstances, and Scotland being taken out of the EU against the will of the people of Scotland was explicitly stated as an example of such a change in circumstances. The voters of Scotland agreed, and returned a pro-independence majority to Holyrood. That was the first validation.

READ MORE: 'Invisible' Tory MPs are called on to stand up for Scotland at their party conference

The second validation came when the Scottish Parliament voted through a bill giving the Scottish Government the right to press ahead with an independence referendum and to negotiate with the Westminster Government in order to bring that about.

That’s how democracy works. Ruth Davidson conceded as much when she said in 2014 that the way to get a referendum was for the pro-independence parties to get a majority in the Scottish Parliament and to vote one through. She needs to be reminded of that. She needs to be reminded how democracy works. The Tories lost the election in 2016. The losers don’t get to determine government policy.

The third validation came in the General Election this year. Nicola Sturgeon said that should the SNP be returned as the largest party in terms of votes and the largest party in terms of seats, that would reinforce the existing mandate. The SNP didn’t do as well as they wanted, but they still ended up as the largest Scottish party with more MPs in Scotland than all the other parties combined. To concede that “Scotland doesn’t want a referendum” because the parties that lost the election say so means to concede that the SNP didn’t really win the election at all. It means to concede that a mandate for independence isn’t as valid as a mandate for the Union. That’s not how to win independence. The SNP didn’t do as well as they’d hoped in the General Election, but the reason they didn’t do as well as they might have done wasn’t because they support another referendum.

It was because they failed to explain to the people of Scotland why Scotland needs another referendum. It was because they failed to enthuse and engage with independence supporters and Yes voters and get them out to the polling stations. It was because they tried to back off from the idea of independence, leaving the field clear to the vacuous naw-ness of Ruth Davidson and the Tories whose sole policy was “Scotland doesn’t want another referendum”.

The SNP are always going to be attacked by the British nationalist parties on independence. They have to own the idea, not downplay it. You won’t win independence by being afraid of mentioning independence. The lessons that Scotland should learn from Catalans and Iraq’s Kurdis is that you don’t surrender the cause of independence just because those who are opposed to it are predictably against it.

You don’t surrender the cause of independence just because you won an election but you failed to win it by a sufficiently crushing margin. You achieve independence because you believe in it, but no-one is going to trust you if you don’t act as though you believe in it. You don’t win self-determination without being determined about it. You achieve independence by strength of will.

The reason many independence supporters vote SNP is not that we want to see Nicola Sturgeon lead a devolved administration, not that we want to see SNP MPs in a Westminster Parliament which we don’t wish to have any control over Scottish affairs. We vote SNP because we want independence. We vote SNP because only a pro-independence majority at Holyrood can bring about the only legitimate route to independence – via an independence referendum in which the cause of independence is backed by a majority of Scottish voters.

If the SNP renege on their existing mandate, many independence supporters will think twice before backing the party in 2021. Why vote for an independence party when they don’t bring about an independence referendum even though they achieve a mandate for it?

Scotland needs an independence referendum before 2021, and ideally towards the end of this parliamentary term. In 2012, a majority of Scots didn’t want a referendum, yet once a date was set people became engaged and Scotland changed forever. Scotland can still achieve its historic destiny, but we won’t achieve it if we lose our nerve.