“There is neither Jew nor Greek, there is neither slave nor free, there is no male and female, for you are all one in Christ Jesus.” These words, written by Saint Paul 2,000 years ago, are central to the Christian faith. They speak of a vocation for the universal and point to an ethic of social justice and solidarity. The Christian tradition’s account of the humble circumstances of the birth of Jesus, represented in the nativity scene, is in the same spirit, identifying Christ with the marginal, the maligned and the poor.

It has therefore, for many Christians, been depressing to witness the faith of their churches being used to justify the abandonment of such principles in Europe, Donald Trump’s America and beyond. For liberally minded Christians, 2019 was the latest in a succession of anni horribiles, during which a cultural appropriation of their religion did service for aggressive nationalism, xenophobia, homophobia and anti-environmentalism.

In Poland, the Law and Justice party was re-elected, with the enthusiastic backing of the country’s Catholic establishment. It made the demonisation of LGBT people a key part of the autumn election campaign. In doing so it received the active assistance of the archbishop of Kraków, Marek Jędraszewski, who warned voters that a “rainbow plague” had replaced the “red plague” which blighted the country in the communist era. The country also stands accused of breaking European Union law by refusing to comply with a refugee quota programme, instituted in 2015.

A question of faith

Hungary’s prime minister, Viktor Orbán, has forsaken talk of illiberal democracy and now speaks of “Christian liberty”. Mr Orbán’s ambition appears to be to turn Budapest into the capital of rightwing Christian thought, an arch-conservative counterpoint to Pope Francis’s Vatican. Last month, at a conference convened in the Hungarian capital to highlight the persecution of Christians in places such as Iraq, Syria and Nigeria, Mr Orbán repeated his argument that Christian culture was under threat from Muslim migration, and warned that the persecution of Christians in Europe was “much closer” than generally understood. The Hungarian Helsinki Committee, a human rights organisation, has accused Mr Orbán of systematically denying food to failed asylum seekers held in detention camps on Hungary’s border – an action it described as “an unprecedented human rights violation in 21st-century Europe.” He has also made homelessness a criminal offence.

Mr Orbán discovered a religious side in his 30s, as the political party he led, Fidesz, moved to the right. In Italy, the leader of the League party, Matteo Salvini, uses Christianity to pursue culture wars relating to migration and national identity. When Mr Salvini, as minister of the interior in Italy’s previous government, proposed in 2018 that crucifixes should be displayed in all Italian public spaces, including ports he had closed to vessels carrying rescued migrants, he was reprimanded by a close adviser of Pope Francis. The Rev Antonio Spadaro tweeted: “The cross is a sign of protest against sin, violence, injustice and death. It is NEVER a sign of identity. It screams of love to the enemy and unconditional welcome.” But Mr Salvini has since doubled down on his politicisation of Catholic symbols, claiming he is “the last of the good Christians”. Support for him among practising Catholics is high.

The battle to defend the rights and human dignity of all, irrespective of gender, race or sexuality, is having to be fought all over again. But the theological roots of that liberal vision in a Pauline notion of universality – “all are one in Christ” – is rarely examined by progressives. In an era when Christian ethics are being so brazenly twisted to serve nativism and attacks on minorities, that could be a mistake. Happily, there are signs that this may change in 2020. Some of the Democrat candidates in next year’s US presidential race are wearing their faith on their sleeve to an unusual extent.

The popularity of Donald Trump among American evangelical Christians is well known. In 2016, 81% of evangelicals and a large majority of US Catholics put Mr Trump’s flawed personal morals to one side, voting for a candidate who would fight their corner in culture wars over same-sex marriage and abortion, as well as on migration. The Pew Research Centre survey this year found that only 25% of evangelicals believe that the US has a responsibility to accept refugees. President Trump’s Catholic former adviser, Steve Bannon, has been a prominent promoter of the supposedly “Judaeo-Christian” values that inform Trumpian nationalism.

Straws in the wind

However, Democrat candidates have begun to play this game on their own terms. Elizabeth Warren, the senator for Massachusetts, has frequently referenced the gospel of Matthew, in which Jesus talks of feeding the hungry, clothing the naked and caring for the sick. Pete Buttigieg, the gay Christian mayor of South Bend, Indiana, has explicitly attacked the Republican party’s taste for “cloaking itself in the language of religion”. Mr Buttigieg told an American magazine: “For a party that associates itself with Christianity to say that it is OK to suggest that God would smile on the division of families at the hands of federal agents, [that party] has lost all claim to ever use religious language again.” Last week the influential US evangelical publication Christianity Today called for Mr Trump to “be removed from office”.

Straws in the wind? For both secular liberals and Christians, there are lessons to be drawn from what might be seen as a prophetic alliance between Pope Francis and Greta Thunberg on the most urgent issue facing the world: the climate emergency. When Time magazine made Ms Thunberg its person of the year, the Vatican was quick to celebrate her as “a witness to what the church teaches on the care of the environment and the care of the person”.

The pope has identified the protection of the Amazon rainforest, where this year the greatest levels of deforestation for a decade were recorded, as an environmental priority. But the culture wars being fought in the public square – which have seen Ms Thunberg become a target – are also being played out within the Christian churches. A three-week Rome synod on the Amazon in October was overshadowed by conservative criticism of the Pope’s decision to invite native peoples and welcome their religious symbols. Liberal democracies rightly prize the separation of church and state which emerged following the Enlightenment. But as the reactionary right denigrates ideas of human dignity and equality that can be traced back to the first formulations of early Christianity, liberals of goodwill need to unite across the religious/secular divide in 2020.

• This article was amended on 26 December 2019 because an earlier version gave the plural of annus horribilis as anni horribili. This has been corrected to anni horribiles.