Dumbarton's MSP has made a pitch to become Scottish Labour's deputy leader.
Jackie Baillie wants to become Richard Leonard's number two in a bid to "unite the party".
She is the only politician to have won the same seat since the creation of the Scottish parliament in 1999, but decided to act after watching Labour "decline".
She had hoped to stand with colleague Pauline McNeill MSP and job share the position, but has been told by party chiefs that wouldn't be possible.
Ms Baillie told the Reporter: “I can’t sit on the side lines any longer and watch my party decline. That’s why I am announcing my candidacy as deputy leader of the Scottish Labour Party.
“I am disappointed that my plans to unite with my friend and colleague, Pauline McNeill, have been rejected, but I look forward to working with her to rebuild our beloved party regardless of whether we share a candidacy or not.
“The future of our party is hanging in the balance. We experienced two crushing defeats in 2019 and the Scottish electorate did not feel able to put their trust in Scottish Labour. As a result, the party lost all but one MP.
"The result has meant that communities across Scotland have been subjected to another five years of Tory austerity, on top of the more than a decade of SNP cuts that they have already had to endure."
She added that her aim will be to unite the party to secure its position in Scotland.
Ms Baillie said: “If Scottish Labour does not accept responsibility for the result and take drastic steps to change, then the party will become a residual force in Scottish politics. My aim is to unite the party and bring members together from across the political spectrum, in order to rebuild the Party for the future."
She concluded: “My membership cards say ‘by the strength of our common endeavour, we achieve more than we achieve alone.’ This resonates with me now more than ever.”
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