Sometimes, history gives the sense that you can make a speech, flick a switch, and hey presto, the job is done.
That is the impression given of an example bandied around a lot in the past few days: Tony Blair and Gordon Brown’s pledge in the run up to the 1997 election to accept the then Conservative government’s spending limits for two years.
But the people who were around at the time remember it rather differently. They admit to a rather bumpy few days as hymn sheets were updated and the strength of the new commitment was put to the test.
Wind forward 15 years, and you see a leader of the opposition and shadow chancellor similarly determined to get the message to the public that a future Labour government will be disciplined in confronting the economic challenges facing the country – challenges that have become more pronounced by George Osborne’s failure to return the country to growth.
If we want people to hear our message, we have to keep repeating it and be confident that it is right.
Labour’s opponents are desperate to convince people that Labour cannot credibly argue against a flawed approach while looking ahead to the difficult task of repairing the damage it is creating.
But there is no contradiction. We wish we were not in this position, and Labour would not be doing its job as an opposition if it stopped arguing for the alternative.
Ultimately though, the public also wants to know that any future government will have in place a credible plan for the country as it finds it. That is why it is important to focus on what the economic landscape is likely to be at the next election.
Focusing on the future is uncomfortable for the Tories because it exposes that their plan to balance the books has been spectacularly blown off course. But in politics you should never stop thinking about tomorrow, even if David Cameron would rather you didn’t.
John Woodcock is Labour MP for Barrow and Furness, and a former spokesman for ex-prime minister Gordon Brown