In Scotland, it brings to an end the dominance of the Sturgon-Salmond era. Indeed, the SNP has not held a leadership contest for almost twenty years because Ms Sturgeon was the obvious successor when Alex Salmond, her former ally and mentor, stepped down in 2014.
Across the rest of the UK, it is the latest signal that the political winds may be shifting.
This shift in leader and possibly in the political direction of the SNP could represent a rare opportunity for Labour to regain ground in Scotland. It is this ground which would be a crucial factor in the party winning any election majority next year.
Labour used to dominate Scotland until 2015 when, in one of the most bruising election defeats in recent history, the party lost all but one of its constituencies. It’s fall north of the border also played a significant role in the shock majority victory enjoyed by David Cameron’s Conservatives.
At the time, reports were of an “unprecedented” landslide victory for the SNP and it seemed like Labour would be – as far as Scotland was concerned at least – left in the political wilderness for years to come.
The resignation of Ms Sturgeon is by no means reason to believe Labour will enjoy a nailed on victory in Scotland. Supporters of the SNP are often such because of their deeply-held constitutional beliefs on Scottish independence and, in more recent years, their Brexit beliefs.
And Labour is not proposing to hold another referendum on Scottish independence, nor is it suggesting it will water down the Tory Brexit. So there is, in theory, nothing for SNP voters in Sir Keir Starmer.
But the significance of this moment of political change and opportunity is not lost on Labour. Sir Keir has been quietly visiting Scotland on a regular basis since Ms Sturgeon announced she was stepping down. And the Scottish Labour leader, Anas Sarwar, has been pushing a message that Scotland needs a “change” – in party, in vision, in direction. It is the same message the Labour party is employing across the rest of the UK.
Any momentum for Labour could become ever stronger if the election of a new leader threatens the SNP-Green coalition currently operating in Scotland.
But the SNP faces a choice between continuity or change – and either of these would be a political gift for Sir Keir’s party.