Roy Moore and Doug Jones are set for a photo finish on Tuesday night as they head towards the conclusion of the most bitterly fought Senate contest in recent history.

Alabama is traditionally a Republican stronghold but multiple allegations that Moore abused teenage girls when he was in his 30s have made it a close race, with Jones hoping to be the first Democrat senator in the state for two decades.

Among the most controversial aspects of the campaign is Moore's dogged support from evangelicals, who make up half the population of Alabama.

Even in the wake of multiple scandals evangelicals have stuck by Moore with several prominent evangelical leaders speaking in support of him. Franklin Graham, son of the famous evangelist Billy and strong supporter of Trump, came out fighting for Moore. 'The hypocrisy of Washington has no bounds,' he tweeted. 'So many denouncing Roy Moore when they are guilty of doing much worse than what he has been accused of supposedly doing. Shame on those hypocrites.'

To understand why evangelicals are so determined in backing Moore, we must look at his history.

1. Roy Moore speaks evangelicals' language

The former Alabama Supreme Court Justice, who was removed twice for violating judicial ethics, is a longstanding member of the evangelical club.

He regularly cites Bible verses to explain his action and his final tweet before polling day sums up precisely why evangelicals want him as their senator.

He wrote: 'I want to Make America Great Again with President Trump.

'And I want to Make America Good Again by returning to the acknowledgment of God!'

One of the times he was expelled was when he ignored a court ruling instructing him to remove a monument to the Ten Commandments in his office as Supreme Court Justice.

In February when talking about the September 11 attacks Moore cited Isaiah 30:12-13, saying: 'Because you have despised His word and trust in perverseness and oppression, and say thereon ... therefore this iniquity will be to you as a breach ready to fall, swell out in a high wall, whose breaking cometh suddenly at an instance.' Moore then noted according to CNN: 'Sounds a little bit like the Pentagon, whose breaking came suddenly at an instance, doesn't it?' He added: 'If you think that's coincidence, if you go to verse 25: "There should be up on every high mountain and upon every hill, rivers and streams of water in the day of the great slaughter when the towers will fall."'

In short Moore speaks evangelicals' language. He is one of them and has been for a long time. They are not prepared to abandon him because of reports in the apparently 'fake news'.

2. Abortion and gay rights

The single most important issue for American evangelicals is abortion, closely followed by gay marriage.

And Moore is right on message on both.

In 2005 the former judge said: 'Homosexual conduct should be illegal today.' He added in an interview televised on C-Span that homosexuality was 'immoral' and 'detestable' and violates the moral code.

More recently in a September 2017 debate he said that 'sodomy [and] sexual perversion sweep the land'.

On abortion Moore has used his rallies to make the oft promised declaration he would fight for the complete repeal of Roe v Wade, the Supreme Court case that made abortion legal across the US.  

For Jones, despite his clean record compared to Moore's scandals, his position on abortion is an insurmountable obstacle for evangelicals. 'The biggest single obstacle is being a Democrat. The fact he's pro-choice reinforces that,' said Gary Nordlinger, a professor of political management at George Washington University.

3. Donald Trump backs Moore

Despite originally backing Luther Strange in the primary stage, the president announced he would support the scandal-hit Moore, although he has not made any campaign appearances for him.

'We cannot afford – this country, the future of this country – cannot afford to lose a seat in the very, very close United States Senate,' Trump said on Friday with Republicans holding a slim 52-48 majority in the Senate.

Describing Moore's Democratic opponent, Doug Jones, as a 'total puppet', Trump said: 'He will never, ever vote for us. We need somebody in that Senate seat who will vote for our Make America Great Again agenda.' 

Trump's plea to Alabama residents is based not specifically on Moore's credentials but on his own need for another Republican in Senate. Although white evangelical support for Trump has plummeted 17 points in the last 10 months, they are still enamoured with their President and Trump's backing will persuade many floating voters.

The President's support is also significant in what it means for the Republican party as Moore, despite winning the Republican nomination, is still viscerally opposed by the hierarchy in the party. Senate majority leader Mitch McConnell has said he believes the multiple women who accused Moore of abuse and said the Senate ethics committee would investigate him were he to win.

Other prominent figures have also spoken against him with 2012 Republican presidential nominee Mitt Romney tweeting: 'Roy Moore in the US Senate would be a stain on the GOP and on the nation. Leigh Corfman and other victims are courageous heroes. No vote, no majority is worth losing our honor, our integrity.'

But Moore is backed by Trump's former White House strategist Steve Bannon who is mounting a challenge on the Republican establishment.

4. Roy Moore is a fellow rebel

Moore used his final push before polling day to reinforce his image as the persecuted underdog.

Attacking the 'fake news' and promising to 'drain the swamp', Moore plays into the evangelical mindset of being an unjustly attacked but righteous minority, taking on the big, bad liberal establishment in Washington.

He is 'their man' sent to do God's bidding. And the more he is attacked, the more he relishes the image of a righteous rebel.

It fits with evangelicals' powerful motif of being persecuted for doing God's work and it also fits into Trump's own carefully constructed image of being a rebel. His open attacks on his own party play into evangelicals' own sense of being betrayed by Republicans who failed to deliver the sweeping conservative reforms they promised.