David Cameron is expected to conduct a significant reshuffle after the EU referendum (assuming he wins – if he loses, it will be someone else’s reshuffle). There is no reason to think he will bring that forward now, and so it is likely he will respond to Iain Duncan Smith’s resignation with a minimalist shakeup, promoting someone to fill the gap.
But who?
Cameron may well be tempted to go for someone safe. Greg Clark, the bright, technocratic, consensus-seeking communities secretary, would be a sound choice. He could be trusted to defuse to controversy about PIP, and also get to grips with the administrative problems bedevilling universal credit.
Harriett Baldwin, the economic secretary to the Treasury, is another potential pick. She is a former member of the work and pensions select committee, and before being promoted to the Treasury, she was parliamentary private secretary to Mark Hoban, then a junior minister in the DWP.
Cameron would then have to fill a vacancy at communities, or environment or energy. Will Priti Patel get her chance? As employment minister, she attends cabinet, but she is not technically cabinet rank. Putting her in the cabinet would ensure that one Brexit minister (Duncan Smith) was replaced with another, which could be useful in terms of assuring Brexit Tories that they are being treated fairly.
Appointing her would improve the diversity of the cabinet. And it would have the added advantage, perhaps, of partially silencing one of Vote Leave’s most vocal spokeswomen, because having to master a new brief would give Patel less time to fight the EU referendum battle.
Another possible replacement for Duncan Smith would be Mark Harper, the chief whip. He is a former disability minister and was well respected by the disability lobby. Like Clark, he could also be trusted to dismantle the Tory rebellion over PIP cuts.
There is also one much bolder step that Cameron could take. Boris Johnson has been promised a cabinet job once his term as London mayor is over and, given that he has just over a month in office to go, Cameron could just about justify giving him a department to run now. The cabinet job promise was made before Johnson decided to campaign for Britain to leave the EU, and now he is certainly seen as a hostile force by Cameron.
But perhaps Cameron may gamble that forcing him to get to grips with the complexities of the welfare system might help to neutralise him in some way.
It is very, very unlikely (not least because Johnson is fairly hopeless at detail, and at DWP detail is paramount), but stranger things have happened.