In the past week, news broke that British Challenger 2 tanks were being used by Ukrainian forces during a major push into Russian territory. This caught a lot of attention, especially in the UK, where government officials were quick to respond. For the previous two days, people close to Keir Starmer, the UK's opposition leader, and John Healey, the defense secretary, had been discussing just how open they should be about Britain’s growing role in the conflict. 

Britain’s involvement...