The scary social media tactics used by the Islamic State to recruit ISIS brides.

In recent weeks the news of ISIS brides wanting to return to Western nations has been dominating headlines.

Women such as Shamima Begum are living in refugee camps, pleading with their home countries to allow them to return.

In most cases, they are being denied.

Listen to The Quicky: What happens when ISIS brides want to come home? Post continues after audio.

But how did they get there? What kind of propaganda did the Islamic State put out there to get these teenagers – some as young as 15 – to leave their lives to join the fight in Iraq and Syria?

It turns out, exploiting typical teen desires and using platforms they were already familiar with – namely social media – was a major part of the IS recruitment drive.

Jacinta Carroll, a senior research fellow in counter terrorism at the Australian National University’s National Security College told Mamamia‘s new podcast The Quicky the Islamic State was very good at honing in on the natural desire for justice that teens and youths have.

She said those who joined the caliphate had some kind of precondition.

“And that is either that the person feels strongly about a particular issue, they might come from a family or identify with a particular group that feels that there is some kind of injustice, but also what we’ve seen in those cases that we’ve been able to dive into, those people who have come out of Iraq or Syria… Is that many people, particularly those who were from the west, is that they were driven from the sort of thing that drives a student to protest,” she explained.

“Most of us in our youth and teens and early 20s have a strong sense of social justice and trying to create a new world. Islamic State was very effective at capturing that, honing in on that and of course not leaving it at leading a protest at a school or university.”

She said ISIS was very good at creating a romanticised version of what lives could be like for these young people in the Islamic State.

For women, the idea of finding "love with a very honourable warrior" was presented. That the women were princess' that were "protected and respected".

The violent reality of the fighting in Iraq and Syria was glossed over. It was more about the opportunity to create a new, free world.

Helen Powell, research fellow in the program of extremism at George Washington University told host Claire Murphy that social media also played a major role in recruitment.

Members of the caliphate participated in individual, grassroots propaganda and recruitment that worked in tandem with the more strategic initiatives from ISIS core media.

She cites the case of Zehra Dumann, a young woman from Melbourne who had a large social media presence.

"She was tweeting about the caliphate. She actually had an ask.fm page where she would answer questions and defend ISIS practices and offer even to help anonymous users find jihadist husbands.

"While she didn't participate in quite a lot of direct recruitment, she was definitely facilitating and encouraging membership across a bunch of different social media platforms."

As ISIS lost almost 100% of its territory in Iraq and Syria in the last couple of years, researchers have witnessed a major decline in successful recruitment.

These women who joined the group - many as young, naive teenagers - are forced into refugee camps, denied entry or stripped of citizenship from their former homes in the West.

As Carroll explained, the debate about whether ISIS brides should be allowed 'home' seems simple on the surface, but many governments are not prepared.

"At a simple level, the debate is 'she wants to come home, even if she did something wrong she can come home and face justice', but that assumes that the home state has effective laws to be able to prosecute someone who has been a foreign fighter," she said.

In the case of Shamima Begum, who wants to return to the UK with her newborn son, it is possible that the laws are just not developed enough to ensure she is held accountable for her crimes.

"The UK for example, might be in the case of this young woman, be able to mount the case against her but its almost impossible to have a brief of evidence to do it and the laws that she's potentially broken aren't that well developed.

"By comparison, in Australia we have an offence called the 'declared areas offence' that was specifically put into place for foreign places.

"It said there are a few places in Syria and Iraq like Mosul and Raqqa we know that Islamic State completely controls these cities, so if you were found to be there, unless you were a journalist or you had legitimate humanitarian work or you were working for a government doing activity there, unless you were doing that you were probably part of ISIS."

Australia's laws mean that those guilty of fighting in foreign places can be prosecuted, but many other countries have not advanced their laws enough.

Given how many fighters left to join Islamic State and will want to return following its demise, nations around the world will need to scramble to make sure their laws are up to scratch.