George Galloway takes his seat in the House of Commons. Ukip's leader, Nigel Farage, strides around the political stage with renewed swagger, hinting at defections from the Conservative party. An independent candidate in London's mayoral election attracts flattering attention by claiming to speak for the people and not the parties. The cliché of disillusionment with mainstream parties is suddenly accompanied by vivid images of self-confident figures flexing their muscles from the outside.

Their rise is wholly unsurprising. Indeed, the surprise is that more of them do not surface to dazzle fleetingly. The political narrative has taken hold that life is not easy for any of the familiar parties. Voters blame Labour for the economic crisis, but note that the two Coalition parties have not improved the economy. In such circumstances some voters look elsewhere. Given the intensity of the anti-politics culture when the economy was booming, a further intensification is inevitable as the economy sinks.

The eccentric mayoral contest in London reflects the disillusionment, with polls suggesting no great enthusiasm for the two main candidates. But to some extent the attitude of the critics highlights the confusion that marks the current hostility towards the so-called mainstream. The critics tend to be against control-freakery from the centre of orthodox parties. Yet Ken Livingstone was selected in an election of party members. If Ed Miliband had fixed the selection, the candidate might have been more to the liking of those who are Labour supporters who will not vote for Livingstone.

In the early 1980s, the Labour leadership was vilified in the media for having no control over the weird candidates being selected in some seats. Neil Kinnock was widely praised when he seized a degree of power over the selection process. Now control from the centre of any mainstream party is impossible, and attempts to pull levers cause a Twitter storm within seconds. Leaders have lost control and yet will face the consequences if the candidates they do not select are poor.

The conundrum about control freakery and losing control is one example of the many dilemmas facing leaders of the main parties. That is politics in the real world, a constant negotiation of impossibly high hurdles. Leaders of the mainstream parties must seek the widest possible alliance of support while retaining connection with the values their parties are supposed to espouse. This immense task is not a science and is in some ways closer to an art form.

Tony Blair was too defensively preoccupied by what he imagined to be the inflexible concerns of newly acquired Middle England supporters. In opposition, David Cameron failed to move as far as was necessary towards the centre ground, and now leads a government of the radical right that still manages to alienate parts of the Conservative right. Ed Miliband is viewed with dismissive wariness by newspapers read by Middle England for being on the left, and voters in Bradford West who worry that he is nowhere near left-wing enough.

Getting the balance right is the essence of leadership and involves making tough decisions every day of the week. Blair once described the decisions he faced on a daily basis as, "do I cut my throat or slit my wrist?" There are few easy options.

The independents and, to some extent, the smaller parties are unburdened by such tedious matters as to how to win power. Voting for them is the equivalent of the cathartic scream or moan. What they say is not only untested by power, but the need to seek power. Without power they can achieve nothing. Some of them are no doubt figures of integrity and principle. But they are part of an anti-politics culture and not a solution to it.

Galloway can do little for the voters of Bradford West because he will not be forming a government at the next election. In the 2001 election, the Wyre Forest constituency elected a non-party MP to campaign against cuts to local health facilities. He made no difference, at least in comparison to the big increases in investment carried out by a party elected to power.

I am told that the independent candidate in the London mayoral election, Siobhan Benita, has many attractive qualities, but I read her pitch and am suspicious. She writes on her website: "I am not a party politician and won't waste my time – or yours – fighting tired political battles. I am in touch with Londoners and understand their day-to-day concerns."

What does she mean by "tired political battles"? Democratic politics depend on the resolution of differences through political battles rather than the military alternative. It is too easy to claim that they can be transcended with the wave of a charming wand, in the same way that it is a piece of cake for Ukip to pretend from the sidelines that the UK can be independent in an interdependent world.

s.richards@independent.co.uk