Idon’t want to be priggish. I accept that when you are fighting the fascistic you have to win and not be too picky about how you do it. But Labour’s victory over George Galloway in Batley and Spen should make you wonder how a centre-left party can ever win back national power. The great realignment of politics across the west is meant to have left the left with one option: building a “rainbow coalition” of liberal graduates, ethnic minority voters, grateful for the educated’s opposition to racism, and all other victims of prejudice and discrimination. The US civil rights leader Jesse Jackson ran with the rainbow coalition slogan in the 1980s, as he tried to secure the Democratic nomination. He failed but offered the hope that eventually “the desperate, the damned, the disinherited, the disrespected, and the despised” would come together and win. Not today: the rainbow coalition is a coalition of losers now, whose members are too concentrated in the cities to beat a right that can win in constituencies across the country. But one day. Surely. Or perhaps not, unless the centre-left can work out what to do when the colours of the rainbow clash. I called George Galloway fascistic. Even now there are many who find the plain use of language disconcerting. Galloway came from the left, they say, but then so did Oswald Mosley. He led the demonstrations against the Iraq war of 2003, and those who marched behind him either did not know or did not care that he had addressed Saddam Hussein as “sir” and “saluted” him in 1994 after the dictator’s genocidal campaign against Iraq’s (largely Muslim) Kurdish minority. He went on to praise the “reforming zeal” of the Syrian dictator Bashar al-Assad, as Vladimir Putin waged war on the (largely Muslim) Syrian population. In Batley and Spen, he said his aim was to topple the “Zionist” Keir Starmer. With a weary inevitability, he then had to sack one of his aides who was exposed as a denier of the Nazi extermination of European Jewry, while a group of Galloway’s supporters organised an intimidatory and homophobic campaign against the Labour candidate, Kim Leadbeater. The colours of the rainbow have never been on display in his career. Just the red and brown of the old pact between far left and far right. The tongue-tied embarrassment might once have been shame about allying with such a man. But most on the centre-left have seen through Galloway by now. Rather the embarrassment comes because Galloway appealed to largely Muslim voters, who are meant to be a happy part of the rainbow coalition of the oppressed. Not exclusively. The white far left, in the form of the Socialist Workers party, and the Corbynites were Galloway’s eager helpers, and the Batley and Spen results suggest his anti-LGBT stance may have attracted the votes of white conservatives. But it remains clear that a demagogic party that is conspiracist, culturally rightwing and radical in its opposition to a carefully selected list of oppressive regimes did well with a section of the Muslim vote. Just as a culturally conservative but economically leftwing party would probably do well with a section of white voters, as Boris Johnson appears to half grasp. People don’t want to call Galloway fascistic because it would imply his supporters backed a foul thug. The notion that the far right can only ever be a white party explains part of it. As does the fear that the statement “some Muslims vote for extremists” will be rapidly turned into “all Muslims are extremists”. In any case, Leadbeater faced down a hate-filled campaign and her victory honoured her murdered sister, who supported the White Helmet movement that tried to save the victims of the murderous assaults of Assad. The Conservative party from Johnson down hoped to benefit from Galloway’s abuse of Labour and went absent without leave from the fight against him. Criticising Labour in these circumstances feels stingy. Yet, when a country faces Conservative rule for as far ahead as anyone can see, criticisms must be made. Labour might have explained to conservative Muslims that Starmer’s policy on Israel was no different in theory to Jeremy Corbyn’s: a two-state solution. The change that Galloway and many on the far left cannot abide is that the conspiracy theories that accompanied Corbynism have gone. If Muslim voters had still stuck with Galloway after that, Labour would then have had no option but to shrug and move on. Instead, Labour issued leaflets denouncing the Tories as the friends of Narendra Modi, and the enemies of the oppressed Muslims of Kashmir. As Labour MPs with Indian minorities in their constituencies told me, the effect was instant. Their inboxes filled with complaints that Labour was running on an anti-Indian ticket. An effort to placate one part of the rainbow coalition succeeded only in alienating another. The traditional objection to identity politics is that they deny individuality. They do, but the argument does not always hold. If individuals become convinced that a party hates them because of their real or perceived identity, they strengthen that identity and fight back. The Conservatives did not fail to attract black and Asian voters for a generation after Enoch Powell’s “rivers of blood” speech because they opposed its monetarism. Nine out of 10 Jewish voters did not refuse to vote for Labour under Corybn because they liked privatised railways. Both saw political movements that appeared to despise them and reacted accordingly. The thinktank British Future once suggested that Labour at its best is a “bridging party”. It had integrated the working class and postwar Commonwealth immigrants into British politics. It should carry on encouraging all groups to exercise their democratic right to make their cases, and then judge which causes to adopt against its values. A party that acts as a bridge is the opposite of the closed parties of politicians as superficially different as Galloway and Trump. But it is not a rainbow coalition. It does not pretend that there are no conflicts of values and interests, and no need for hard decisions because every group it hopes to yank together is by definition living in harmony. A recognition of the need to make choices would be a welcome advance. The trouble with rainbows is that they fill the sky with shimmering beauty for a moment and then vanish as if they were never there. Nick Cohen is an Observer columnist