Usually, in politics, a U-turn is the right thing to do. If a leader changes from an unpopular policy to a more popular one, they tend to emerge embarrassed but strengthened.
This U-turn – a bid to stave off a mass rebellion over plans to cut £5bn from the benefits bill – is different. Mainly because Keir Starmer has switched to a policy that is more popular with his MPs but less popular with the voters. It will be particularly unpopular with the voters when they have to pay for it in higher taxes.