May makes a complicated but economically well-thought out policy to address a problem, releases it, finds out it is wildly unpopular, u-turns. (See tax-credits, social care, self-employed NI contributions).
Corbyn makes a bad-thought out policy, releases it, is questioned about it in interviews, makes something up about spending enough money to keep everyone happy, backtracks later because he hasn't a clue what he is talking about. (See social housing, taxation, student loans, benefits cap, public sector pay cap, policing or basically anything that involves him spending billions in public money.)
