Mr Ashdown says everyone must be vigilant against racism "day in, day out".
The full report of the inquiry into Stephen Lawrence's death is to be published on Wednesday.
Parts already leaked suggest it will accuse the Metropolitan Police of institutionalised racism.
But in a speech in central London on Tuesday, Mr Ashdown will say the problem is a far wider one.
"The fact is that racism is endemic in our society," he will say.
![[ image: width=150]](/olmedia/280000/images/_284459_racist150.jpg)
"Stephen Lawrence died, at least in part, because we have not been sufficiently vigilant against racism in our lives, our attitudes and our society."
He will claim that the tradition of policing with the community's consent has been lost in much of the UK, particularly the inner cities.
The Lawrence report "could be its death knell or, just possibly, the spur for its rebirth".
Asylum 'hysteria'
Mr Ashdown will also reaffirm his party's opposition to the Immigration and Asylum Bill, debated at second reading in the Commons on Monday.
The government has faced criticisms from its own backbenchers for plans to offer asylum-seekers benefits in the form of goods and services instead of cash assistance while their cases are processed.
Ministers say the changes will make the immigration system faster, firmer and fairer.
Mr Ashdown will protest that asylum-seekers are often described in "the language of scapegoating" and "unjustified hysteria" which governments do not repudiate fast enough.
"Unless leaders will set the example and take the risks to stake out strong positions, we can never win the battle to suppress racism."
Challenging racism
Mr Ashdown will speak as he accepts the Commission for Racial Equality's Leadership Challenge from CRE chief Sir Herman Ouseley.
![[ image: width=150]](/olmedia/280000/images/_284459_cre150.jpg)
The challenge urges those with influence to use it against racism.
The Liberal Democrats, who say they had more ethnic minority candidates at the 1997 general election than any other party, are unveiling a series of initiatives to enhance the role of the party's ethnic minority members.
Black and Asian members will be invited to "shadow" Lib Dem MPs to give them first-hand experience of parliamentary life and encourage them to put themselves forward as candidates.
A similar scheme is already in operation to encourage women to seek selection.
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Commission for Racial Equality
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