Den 6. januar 2020 meddelte hun, at hun stiller op til valget til formand for Labour.<ref>{{Cite news|url=https://tribunemag.co.uk/2020/01/rebecca-long-bailey-labour-leadership-socialism|title=To Win We Must Unite All Of Labour's Heartlands {{!}} Rebecca Long-Bailey|last=Long-Bailey|first=Rebecca|date=6. januar 2020|work=Tribune|access-date=6. januar 2020|language=en-GB|}}</ref><ref>{{Cite news|url=https://www.bbc.com/news/uk-politics-51012381|title=Long Bailey becomes sixth candidate in Labour race|publisher = BBC News|date=7. januar 2020|access-date=7. januar 2020|language=en-GB}}</ref> Hun nåede blandt topkandidaterne til formandsskabet, men tabte den afgørende afstemning til [[Keir Starmer]].
Levende_personer Politik Samfund