Was Jesus Christ a lefty? Philosophers, politicians, theologians and lay members of the various Christian churches have long been divided on the subject. The former Soviet leader Mikhail Gorbachev once declared: "Jesus was the first socialist, the first to seek a better life for mankind." The Venezuelan president, Hugo Chávez, went further, describing Christ as "the greatest socialist in history". But it's not just Russian ex-communists and Bolivarian socialists who consider Jesus to be a fellow-traveller. Even the Daily Mail sketch-writer Quentin Letts once confessed: "Jesus preached fairness - you could almost call him a lefty."

That conservatives have succeeded in claiming Christ as one of their own in recent years - especially in the US, where the Christian right is in the ascendancy - is a tragedy for the modern left. Throughout history, Jesus's teachings have inspired radical social and political movements: Christian pacifism (think the Quakers, Martin Luther King or Bruce Kent in CND), Christian socialism (Keir Hardie or Tony Benn), liberation theology (in South America) and even "Christian communism". In the words of the 19th-century French utopian philosopher Étienne Cabet, "Communism is Christianity . . . it is pure Christianity, before it was corrupted by Catholicism."

These days, however, the so-called God-botherers tend to be on the right. In his book God's Politics, the US Evangelical pastor Jim Wallis, spiritual adviser to President Obama and Gordon Brown before him, laments the manner in which Jesus's message has been misinterpreted by the warring political tribes, writing of how the right gets Christ wrong, while the left doesn't get him at all.

He reminds his readers that being a Christian is not necessarily the same as being a "right-wing Christian fundamentalist", and that the Bible's focus on social justice and the poor shows that economic life should be organised around the needs of society's weakest and most vulnerable members.

The unemployed son of two asylum-seekers - Joseph and Mary - who fled to Egypt to avoid the genocidal tendencies of King Herod, the Jesus of the Gospels is a bearded, sandal-wearing, unmarried rabbi from Nazareth with all the personal traits of a modern revolutionary. In an essay published in 2007, the Marxist literary critic Terry Eagleton noted that the Gospels present Christ as "homeless, propertyless, peripatetic, socially marginal, disdainful of kinfolk, without a trade or occupation, a friend of outcasts and pariahs, averse to material possessions, without fear for his own safety, a thorn in the side of the establishment and a scourge of the rich and powerful". Eagleton added: "Jesus has most of the characteristic features of the revolutionary activist, including celibacy."

Traits of character aside, where would Jesus stand in the main debates of our time, such as war and peace, wealth and taxation, health care and financial reform? To use the formula made popular by Evangelicals in America (often abbreviated to WWJD), "What would Jesus do?" He would do the same as any self-respecting lefty. Here are five reasons why.

1 Jesus the class warrior

From Cuban communists to New Labour social democrats, a belief in redistributing wealth from the rich to the poor is at the core of leftist thinking. The means used to achieve that redistribution, such as higher rates of income tax, are often decried by conservatives as representing the "politics of envy", a misguided Marxist desire for class war.

Jesus, however, went far beyond the 50p top rate of tax or a bonus tax in his zeal for redistribution and his rhetorical attacks on the richest members of society. To see what the "politics of envy" looks like in the Gospels, turn to Mark 10:21-25. Here, Jesus gives a startling answer to a pious Jewish man who has asked him how he can "inherit eternal life".

21 Jesus, looking at him, loved him and said, "You lack one thing; go, sell what you own, and give the money to the poor, and you will have treasure in heaven; then come, follow me." 22 When he heard this, he was shocked and went away grieving, for he had many possessions. 23 Then Jesus looked around and said to his disciples, "How hard it will be for those who have wealth to enter the kingdom of God!" 24 And the disciples were perplexed at these words. But Jesus said to them again, "Children, how hard it is to enter the kingdom of God! 25 It is easier for a camel to go through the eye of a needle than for someone who is rich to enter the kingdom of God."

Forget taxing the rich until the pips squeak, Denis Healey-style; Jesus declares that the Roman Abramoviches and Donald Trumps of this world will struggle to achieve salvation in the afterlife. Why? "You cannot serve God and wealth," he says (Matthew 6:24). And, according to the epistles, "The love of money is a root of all kinds of evil" (1 Timothy 6:10).

Further, Jesus argues that we have a moral obligation to pay taxes. In one of his parables, he heaps praise on a "righteous" tax collector (Luke 18:9-14). Were he alive today, Jesus would be leading the campaign to crack down on tax-dodging billionaires and multinational corporations. Here, in one of the best-known stories from the Gospels (Matthew 22:17-21), he is challenged by the followers of the Pharisees: 17 "Tell us, then, what you think. Is it lawful to pay taxes to the emperor, or not?" 18 But Jesus, aware of their malice, said, "Why are you putting me to the test, you hypocrites? 19 Show me the coin used for the tax." And they brought him a denarius. 20 Then he said to them, "Whose head is this, and whose title?" 21 They answered, "The emperor's." Then he said to them, "Give therefore to the emperor the things that are the emperor's, and to God the things that are God's."

It perhaps offers a fitting slogan for the placards of UK Uncut, the newly formed group protesting against tax avoidance, at its next high-street demo. In recent weeks, UK Uncut has used direct action to shut down stores owned by Vodafone (accused of being let off £6bn in tax) and the coalition government's "cuts tsar", Philip Green (accused of avoiding a £285m bill by transferring ownership of his Arcadia business empire to his wife, who lives in a tax haven, Monaco). Jesus would approve.

On one occasion, despite telling his companions that he is not liable to pay the "temple tax" that is demanded of every Jewish man in Palestine - because the Father does not require it from his own son - Jesus publicly pays the tax (Matthew 17:24-27). As the Scottish theologian and New Testament scholar William Barclay wrote: "Jesus is saying, 'We must pay so as not to set a bad example to others. We must not only do our duty, we must go beyond duty.'"

2 Jesus the banker basher

In March 2009, the windows of the detached stone villa in Edinburgh belonging to the disgraced Fred Goodwin, former chief executive of the bailed-out Royal Bank of Scotland, were smashed and his Mercedes S600 was vandal­ised. Some complained that the bankers were being made "scapegoats" for the financial crisis. I suspect Jesus might have been tempted to throw the first stone. He had form with "banker bashing", as Mark (11:15-17) testifies.

15 And he entered the temple and began to drive out those who were selling and those who were buying in the temple, and he overturned the tables of the money-changers and the seats of those who sold doves; 16 and he would not allow anyone to carry anything through the temple. 17 He was teaching and saying, "Is it not written, 'My house shall be called a house of prayer for all the nations'? But you have made it a den of robbers."

Tables turned over, wealth scattered, moneymen described as robbers - Christ's "cleansing of the temple" is a blueprint for the direct action against the financial and political elite by left-wing activists today. In Eagleton's words, this was Christ's attack on the "bastion of the ruling class".

3 Jesus the fair-wage campaigner

It isn't a coincidence that the campaign for a “living wage" - the minimum wage required for every worker to earn enough to provide his family with the essentials of life - has been driven by Citizens UK, a collection of urban community and faith groups that includes churches. The Gospels don't quite tell us that Jesus was a trade unionist, but they do suggest he backed a living wage.

Matthew 20:1-16 narrates the "parable of the workers in the vineyard", which tells of five sets of labourers who arrived for work very early in the morning, at 9am, at noon, at 3pm and at 5pm. They are all paid at 6pm and each labourer receives the same amount - one denarius, as agreed to with their employer. Unsurprisingly, those who arrived earlier and did more work complained that they had received the same pay as those who had come later: "These last worked only one hour, and you have made them equal to us who have borne the burden of the day and the scorching heat." But, for Jesus, the casual labourers who came to work for the landowner in his vineyard had basic needs that had to be satisfied, and those who had come late had been struggling to find work in a laissez-faire market: "No one has hired us," the last labourers tell the landowner. "From each according to his ability, to each according to his need," in the words of Karl Marx.

According to Jack Mahoney, emeritus professor of moral and social theology at the University of London, this parable allows us to think of the employer "as not being simply a generous, or overgenerous, employer, but in fact as being a just employer", someone who pays "a daily living wage".

4 Jesus the NHS champion

Jesus was a healer. The Gospels contain countless stories in which he helps the blind to see, the deaf to hear and the lame to walk. There is little evidence that he charged for his services, demanded to see an insurance card before offering treatment, or profited from his miraculous ability to bring the dead back to life.

He called on his disciples to do the same, instructing them to go into towns and "cure the sick who are there" (Luke 10:9). Again, there is no discussion of payment or fees or charges. Indeed, throughout his life, in word and deed, Jesus was a champion of universal health care, free at the point of use. He would have been an ardent and passionate defender of the NHS from free-market "reforms".

Take the story of the synagogue leader Jairus and his terminally ill daughter, and that of an unknown, destitute woman who has been haemorrhaging for 12 years and has "spent all that she had" paying physicians (Mark 5:21-43). Jesus heals both the sick daughter and the destitute woman. The linking of these two stories reminds us how sickness and ill-health are universal; we all, regardless of social status or bank balance, need access to health care at some stage in our lives.

The American academic, blogger and Baptist minister Drew Smith explains the political significance of these verses. "In a market-driven system of health care, the unnamed woman would have perhaps gone untreated, but Jairus would have had the health care he needed for his daughter. After all, Jairus is a man of means . . . But in stopping to heal the unnamed woman instead of proceeding to Jairus's house uninterrupted, Jesus also rebuked a system that offered preferential treatment for those like Jairus who have power, status and money."

It is no wonder that in the heated town-hall debates that were held across the US in the run-up to the signing of the Obama administration's health reform bill, which extended health-care coverage to an estimated 32 million uninsured Americans, some liberal activists carried placards proclaiming: "Jesus would have voted Yes".

5 Jesus the anti-war activist

Would Jesus have backed the Iraq war? Or would he have joined the two million anti-war protesters marching through the streets of London in February 2003? How about the war in Afghanistan? Stay the course? Or do a deal with the Taliban and bring the troops home? WWJD?

Jesus's pronouncements on war and peace, action and reaction, confirm his preference for non-violent struggle. "Blessed are the peacemakers," he says, "for they will be called children of God" (Matthew 5:9). And: "You have heard that it was said, 'An eye for an eye and a tooth for a tooth.' But I say to you, Do not resist an evildoer. But if anyone strikes you on the right cheek, turn the other also" (Matthew 5:38-39). He also says: "Put your sword back into its place; for all who take the sword will perish by the sword" (Matthew 26:52).

Christian peaceniks point to these verses when challenging the militarism of ostensibly Christian nations such as the US and the UK.

“I want a faith that takes Jesus seriously in foreign policy," says Jim Wallis. "When Jesus says, 'Blessed are the peacemakers,' what does that mean? This is what Jesus taught. He doesn't say the 'peace lovers'. Blessed are the peacemakers." Wallis also says: "I think it's not credible to believe that Jesus's command to be peacemakers is best fulfilled by American military supremacy through the imposition of Pax Americana."

In his new memoir, Decision Points, the former US president and born-again Christian George W Bush recalls how he arrived at his decision to approve a request from the CIA to waterboard Khalid Sheikh Mohammed, the alleged mastermind of the 11 September 2001 attacks. "I thought about the 2,973 people stolen from their families by al-Qaeda on 9/11 . . . 'Damn right,' I said." But Jesus, the man once identified by Bush as his favourite political philosopher, has little time for such talk of vengeance and retribution. In Luke 6:27-28, he says: "Love your enemies, do good to those who hate you, bless those who curse you, pray for those who mistreat you."

The ex-president is said to have confessed to a group of Palestinian officials that God told him to "fight those terrorists in Afghanistan . . . and end the tyranny in Iraq". Given Jesus's rhetoric on non-violence and "peacemakers",

I suspect the voices in Bush's head were not those of God, or his son.

Love your enemies. Renounce your wealth. Pay your taxes. Help the poor. Cure the ill (for free). These are the hallmarks of a left-wing, socialist politics. What Jesus wouldn't do is allow the rich to get richer, give a free pass to the bonus-hungry bankers and invade one foreign country after another. It is difficult to disagree with Wallis when he says: "The politics of Jesus is a problem for the religious right."

Mehdi Hasan is senior editor (politics) of the New Statesman. Read his blog here.