In early April, France's 11 presidential candidates sparred in a televised debate. Devastating comments from fringe candidates and flashes of brilliant repartee made for lively viewing. I found the accompanying Twitter commentary to be hilarious, until somebody posted the following: 'This would be really funny if it involved any country other than mine.'

There's never been such a wide-open presidential election in the history of the Fifth Republic. Since its establishment back in 1958, you could fairly safely assume that French presidents would represent well-established political parties – until now.

Today, the mainstream political groups look adrift. Both the left and centre/right-wing presidential primaries produced winners that defied the polls. Both are now in serious trouble.

On the right, 'Mr Clean' candidate François Fillon has been formally charged with various fraud offences in relation to allegations of fake parliamentary jobs for his wife and children – and has refused to withdraw, despite an earlier pledge to do so if charges were pressed. On the left, official Socialist Party candidate Benoît Hamon has had a lacklustre campaign and is trailing far behind in the polls. Hamon has lost support to charismatic maverick Jean-Luc Mélenchon on the far left, while to his right, the Socialist candidate has been largely deserted by party heavyweights, now throwing their support behind Emmanuel Macron.

Macron is currently polling neck and neck with far-right Front National candidate Marine Le Pen for the first round, from which the two front-runners go forward to the second.

This is Macron's first election of any kind, following his defection from Socialist prime minister Manuel Valls' government, in which he was an unelected minister. His new political movement is barely one year old. Meanwhile, given all the discord on the left, Marine Le Pen seems all but certain to gain enough votes to be in the final run-off – and to stand a serious chance of winning.

The campaign typifies the anti-system sentiment discernible in many recent ballots. Outgoing president François Hollande's unprecedented decision not to stand for a second term embodies the sense of political and moral bankruptcy that has engulfed the traditional parties. Whether or not the jobs François Fillon claims his family did for him are real, the amounts of money involved and his seeming unawareness of how such sums look to the average French voter make him seem desperately out of touch. The Socialist Party faithful's opportunism in casting their lot in with Emmanuel Macron, a former investment banker whose policy orientations appear to depend on who he last spoke with, looks craven. Against this backdrop, Marine Le Pen has an unnerving knack for the common touch, and an ability to come across as an anti-system candidate – despite being the product of a political dynasty herself.

Christians with traditional values tend to see Fillon, a practising Catholic whose conservative religious beliefs are reflected in his political agenda, as their candidate of choice; but his inconsistencies seem uncomfortably close to the kind of religious hypocrisy at which Jesus directed some of his harshest words. Some evangelicals are openly touting Le Pen, largely on the grounds of defending a so-called Christian nation against hordes of Muslims. Hamon may appeal to more politically liberal Christians with a heart for prison reform and environmental issues, but even they may balk at his support for the legalisation of cannabis and his rather Utopian promise of a universal basic income. At the end of the day, many may vote for Macron, but as the lesser of all evils – a vote by default rather than a firm vote in favour.

Many voters may simply throw their hands up in a suitably Gallic gesture of despair, and abstain. One Facebook poster suggested dropping their voter registration card in the ballot box, but such protests and abstentions will only benefit the extremist parties. In any event, the presidential election looks set to propel France into unknown territory – and that's before the subsequent general election.

So what's a pastor to tell his congregation in such circumstances? Directing church members to vote for a given candidate is clearly not on. I will however be encouraging people to vote, because I strongly believe Christians should be responsibly engaged in the society around them. I urge them to look not simply at what the candidates are saying, but also at their character; and, if they are tempted to make up their minds based on a few hot-button issues, to ensure they don't swallow any camels in the process. The book of Acts tells us that the Bereans checked the Scriptures to see if what they heard from Paul was true (Acts 17:11); today, as followers of the Truth, Christians need to be encouraged to watch out for 'fake news', check a story before sharing it, and learn to think and discern for themselves rather than take refuge in 'alternative facts'.

The way I see it, the prevailing trend in France and other Western nations right now is towards withdrawal, hardening borders, and building walls, be they physical or less tangible ones. By contrast, the Bible portrays the city of God as having no walls at all (Zechariah 2:4)! Whatever the outcome of the forthcoming elections, Christians' counter-cultural, anti-worldly calling is to embody such a city through our openness to those around us. This calling is likely to be put very much to the test in the days ahead.

Like many other countries, France is heading into great uncertainty. This should come as no surprise: the writer to the Hebrews offers us a powerful reminder that God intends to shake everything up, with the 'removal of what can be shaken', even as Christians are receiving a kingdom that is unshakeable (Hebrews 12:27-28). I pray that my adopted nation will be able to ride out these uncertain times and ultimately emerge better off; and even more so, that the Christians of France will rise to the challenge of seeking God's unshakeable kingdom in a way that glorifies him.

Born in the UK, David Buick has lived in France since 1985 and has dual nationality. He is a pastor, prison chaplain, and freelance translator.