The economy - especially the deficit.
So who have the Tories have chosen to be the public face of the election campaign?
David Cameron's all male "famous five" election squad Mr Cameron, Kenneth Clarke, William Hague, Schools spokesman Michael Gove and Shadow Culture Minister Jeremy Hunt, according to briefings to the Mail on Sunday.
What about George?
Wot No Shadow Chancellor. And yet - in spite of the very telling inclusion of shadow business secretary Ken Clarke - the boy George has nothing at all to worry about, say Tory sources.
The Tories deny that Mr Osborne or Mr Grayling have been snubbed. They say Mr Osborne will concentrate on his behind-the-scenes role as the Tories’ Election mastermind and will make occasional public appearances.
However, privately, they admit that Mr Osborne gets low ratings in confidential Conservative polls and was damaged by reports of how he was entertained on Russian oligarch Oleg Deripaska’s yacht in Corfu.
And perhaps we should take a share of the blame.
Might Conservative central office have had spies at the New Year Conference where Vinay Nair won over the panel of dragons and brought the house down with his very amusing two minute pitch of how to make Osborne central to the election campaign.
Or have they just been asking the voters themselves?
The Osborne invisibility strategy suggests that the identity and ideas of the man who would have the lead role in dealing with the economy and public finances are something the Conservatives think they would do very well to keep under wraps.
Alastair Darling and Vince Cable should certainly make smoking Osborne out an important part of the Labour and Liberal Democrat campaigns.
And I imagine the Shadow Chancellor may yet find he has to scale up on the kindness with which his party plans to indulge us all with his "occasional public appearances".
Don't be surprised to read some counter-briefing in the morning papers.
But let's hope it is not quite as chin-itchingly implausible as the Osborne camp's insistence that it was their idea that Dave should bring Ken back in all along.
PS: It is also unclear what is happening to Chris Grayling's impressive political rise - who is also seen by a few in his own party and many of his political opponents as somebody the voters should see much more of.
Perhaps he will have strategic responsibility for statistics, TV listings and campaign gaffes.
The report notes that Grayling was conspicuously absent from the name-checks as the holders of the other major Shadow posts were listed as future Cabinet Ministers by Cameron in his speech last weekend.
So I wonder if Rebekah and Rupert - and their ex-colleage Andy Coulson - are less impressed than they expected to be when The Sun demanded the demotion of Dominic Grieve, as part of what the Spectator called Cameron's "pub ready" Shadow Cabinet reshuffle last year.