By Laura Kuenssberg
BBC political correspondent
So why now? It has been a few weeks since the Archbishop of Canterbury's remarks on Sharia horrified many members of the public and parts of the press.
Mr Cameron said expanding Sharia could create 'legal apartheid'
And very quickly, the three main parties lined up to object too. Their assessments of remarks by Rowan Williams ranged from "unhelpful", to being likely to lead to "social chaos".
But interestingly, the Conservatives' views were represented then not by the leader of the party, but by Baroness Warsi, their shadow communities minister.
Perhaps the party felt it was easier, less inflammatory for the female Muslim peer to get involved.
'Dangerous and illiberal'
Or maybe Team Cameron wanted to wait and see how the story shook down before he weighed in, or perhaps there was just a diary clash that prevented him talking about it.
But on Tuesday David Cameron made his foray in to the debate, quite deliberately and determinedly.
The archbishop's team has not commented on the Conservative leader's stance. They may well choose not to, loathe to reignite the row
And his comments were trenchant too. Saying the archbishop's ideas could create "legal apartheid", and that they were "dangerous and illiberal".
It was a wide-ranging speech clearly designed in particular to put Mr Cameron's views about Sharia law on the record and to shove the debate back into the public's conscious.
Yet so far there doesn't seem to be much appetite to do so in Westminster. The other two main parties have stayed silent on the matter today.
Perhaps because their view of Dr Williams's remarks is not that different to Mr Cameron's. Much of his speech in fact, which discussed the need to strengthen British identity, sounded enormously similar to some of Gordon Brown's previous statements.
And unusually, the Conservative bloggers have not bitten at this story so far. It is rare for them not to dissect a major speech from the party's leader, but this time perhaps they feel it has all been said.
Dr Williams found himself at the centre of a huge row
Even though Lambeth Palace is just across the river, Mr Cameron's message does not seem to have crossed the Thames yet.
The archbishop's team has not commented on the Conservative leader's stance. They may well choose not to, loathe to reignite the row.
So why the silence, given the deafening responses to every twist and turn of the Sharia law debate a couple of weeks ago?
Well it is perhaps an example of the reality that much of the time for something to be news it has to be new.
Mr Cameron's remarks, while strong, echo, rather than contradict comments made by other politicians, and extensively covered just a couple of weeks ago.
And while the Conservatives say they will soon outline policies to improve relations between different communities, there were no clues of any new firm plans today which might have sparked a debate.
So for now, the political row over Sharia law stays muted. But given the sensitivities that surround it, there is no guarantee it will not flare up again.