True dissidents – celebrity or not – play a vital role in democracy. But the celebrity desire to gain political power and social approval breeds intellectual conformity, precisely the opposite of what we need to achieve real changes. Politicians, intellectuals and the public can fall prey to groupthink (We must invade Vietnam to keep the dominoes from falling!) and need dissidents to shake them out of it.

True dissidents claim no expertise; they offer no 10-point plans to fix a problem. They are most effective when they simply assert that the status quo is morally wrong. Of course, they need to be noticed to have an impact, hence the historical role of dissidents such as Lennon who can use their celebrity to be heard.

We’re hardly starved of moral challenges for our leaders today, in an age that has witnessed Abu Ghraib, Guantanamo and enduring wars with unclear objectives and the clearest of casualties. On Bono’s signature issue of poverty, for instance, why not call out a few of the oppressive regimes that keep their people impoverished – as well as the leaders, in the United States and elsewhere, who have supported them with economic and military aid? (Bono has acknowledged that “tinpot dictators” were a problem for aid efforts in the past but has not confronted today’s despots and their enablers in rich nations.)

We need more high-profile dissidents to challenge mainstream power. This makes it all the sadder that Bono and many other celebrities only reinforce this power in their capacity as faux experts. Where have all the celebrity dissidents gone? It’s not a complicated task. All Lennon was saying was to give peace a chance.