When Federal Parliament finally voted on same-sex marriage in December 2017, 14 MPs abstained from the vote in the House of Representatives, along with eight in the Senate.

Just four MPs voted against the bill in the House. But many of those who abstained had been vocal critics of the legislation, including our now Prime Minister, Scott Morrison.

Amid heated debate about whether ministers of religion would be forced to marry same-sex couples — against their teaching of their faith — a proposal was born for amendments that would entrench religious freedom in law.

(The same sex marriage legislation did ultimately contain provisions which meant religious celebrants were not obliged to perform marriage services.)

Mr Morrison was one of the main advocates who argued that questions of religious freedom had to be dealt with at the same time as marriage equality.

But then-prime minister Malcolm Turnbull argued there should be a broader and separate discussion of the issues — since they went beyond marriage — and federal cabinet eventually agreed to appoint former Howard-government minister Philip Ruddock to review the protection of religious freedom.

This context is important to keep in mind now that, almost two years later, we finally have a draft religious discrimination bill to consider.

What's in the draft?

The issue has long been seen as a lightning rod for division within the Coalition. In fact, it is more regularly seen as a political plaything for battles between conservatives and others in the party than as a complex and sensitive issue to be dealt with by the Parliament in the interests of the broader community.

It's sometimes described as no more than an internal Coalition battle, or even as just a wedge against Labor.

There are strongly held views about what religious freedom actually means, and what needs to be protected, on both sides of the argument, and there has been considerable apprehension about what might emerge with the draft bill.

Attorney-General Christian Porter has released a draft which produced some early grumbles from both sides, but which has grounded itself in anti-discrimination law, rather than in religious rights philosophy.

As he has repeatedly said, the Government has sought the shield, rather than sword, approach to the issue, arguing the alternative would leave too many questions for the courts to have to determine.

The interesting parts of the draft are that, while it seeks to protect against discrimination on the grounds of religious belief or activity, it prescriptively defines neither.

A government summary of the paper says:

"Religious belief is intended to include beliefs associated with major faith traditions (such as Christianity, Islam, Hinduism, Buddhism or Judaism) in addition to the beliefs of smaller and emerging faith traditions. However, it is not intended to capture beliefs caused by mental illness or that are motivated by criminal intent. "Religious activity may include participating in religious observances (such as prayers, fasting, ceremonies or other holidays); wearing religious dress (such as a hijab, kippah or kirpan); and not engaging in certain conduct in accordance with religious belief (such as not eating meat or drinking alcohol)."

Folau would have a case

It says you can't be seen to discriminate against someone merely for expressing a genuinely held belief.

In the ubiquitous case of Israel Folau (who was sacked by the Australian Rugby Union for saying on social media that drunks, homosexuals, fornicators and others would go to hell), according to Mr Porter, the bill would "give someone in Israel Folau's circumstance an avenue for complaint" he told 7.30 on Thursday.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 7 minutes 5 seconds 7 m Christian Porter on the draft religious freedom legislation

"That complaint would look like this: My employer puts a condition upon me which has the effect of restricting my ability to express my religious beliefs in my spare time.

"And what this bill says is that if a large employer with a turnover of over $50 million did that, not merely would they have to show that broad condition on the employee is reasonable, but they would have to show that unless that condition were complied with, that they, the business, would suffer undue financial hardship."

Mr Porter argues part of the rationale for this provision on larger businesses is that it is a brake on businesses trying to dictate what their employees say outside work hours, which he argues is a restriction on free speech.

(This sits rather oddly with the increasing moves by the Government to close down this very right for public servants, who would not be protected by this provision).

But a practical advantage of the financial-hardship provision is that it gives a non-philosophical, shall we say, point of assessment, against which tribunals and courts could consider complaints about freedom of religion under this proposed legislation.

Equally, there is a "reasonableness" test in cases of indirect discrimination on religious grounds which should ensure complaints are not frivolous.

There are concerns the legislation would over-ride some existing state anti-discrimination laws, though Mr Porter argues the reality is that there are flaws in state laws which have not helped anybody and the legislation merely says commonwealth law would prevail in contentious cases.

A test of faith

Scott Morrison's leadership on the issue will be viewed publicly through the prism of his own strong religious commitment. ( AAP: Mick Tsikas )

But the great test will be how those who wanted more aggressive freedom-of-religion laws might respond and, in turn, what the Prime Minister has to say.

Liberal Senator Concetta Fierravanti-Wells said on Friday it was "clear from my ongoing consultation and engagement with religious leaders that the bills are likely to fall far short of properly and fully addressing their requirement".

If that proves to be the case, and the draft legislation produced by Mr Porter comes under intense pressure to be hardened up, it creates not just a unique dilemma for the Prime Minister but, without doubt, his most complex domestic challenge.

And the challenge is not of the "challenge to his authority" nature. The challenge is to his capacity for political leadership.

Here is an issue on which he has led the running from the start and, without doubt, is seen in the public mind through the prism of his own strong religious commitment.

But his Cabinet has produced a well-thought-through structure for dealing with this thorny issue and a structure which does provide the capacity for people to be able to speak out in terms of their faith without facing prosecution.

But if conservatives push on the issue, Mr Morrison will have to advocate for policies which may offend the very conservative base to which he appealed when he pushed for this review in the first place.

"I do not want religion to be an issue that divides Australians, it is deeply personal for people, I want to work through it in a way that enhances unity, not for political purposes," Morrison told his party room earlier this year and he has argued equally that he wants to develop a bipartisan position on the issue.

That is going to require some serious and detailed positive advocacy of a difficult issue. It is not something we see a lot of in politics these days.