Centre-back has been a real problem for Liverpool for at least five years now.
There have been plenty of attempts to fix that, but no one has managed to stamp their authority on the position until Virgil van Dijk's enormous move from Southampton in January.
The Dutchman looks set to justify every penny of his £75million transfer fee judging by his performances thus far, and all that really remains for Liverpool is to find a partner for him.
Dejan Lovren is still remarkably error-prone, Joel Matip has struggled to offer consistency in his performances and Joe Gomez is yet to prove he is over the injuries that have blighted his career to this point.
Finding the right man to work with Van Dijk is not as simple as signing the best player money can buy; the Dutchman appears to thrive on being the top dog in defence for Liverpool, organising the shape, taking charge of situations and leading with genuine authority.
That authority is something else Liverpool have to consider; the difference Van Dijk's confidence and determination has made is almost palpable and more of that would be incredibly desirable.
And that us why Jamaal Lascelles, the latest reported target of Liverpool according to the Independent, makes so much sense.
The Newcastle United defender is only 24 and still learning his way in the game but, at the same time, he has captained Newcastle through promotion from the Championship to safety in the Premier League.
Lascelles offers both the authority that Liverpool have found success with, while also offering potential that Jurgen Klopp can help nurture and mould towards what he wants.
We have seen what the Liverpool boss has done with Andy Robertson, Alex Oxlade-Chamberlain and Trent Alexander-Arnold, and what he could do with a player with the potential of Lascelles is a very exciting proposition indeed.