A victory parade was held on Sunday in Iraq to celebrate the defeat of IS after Prime Minister Haider al-Abadi formally announced the victory on Iraqi state television on Saturday evening.
He also declared Sunday as a public holiday.
Ulster Unionist MLA Doug Beattie said the parade in Baghdad was necessary to restore national pride.
Mr Beattie, who served in Bosnia, Kosovo, Iraq and earned a Military Cross for his service in Afghanistan, said: “If we go back two or three years there was a huge national disgrace in Iraq whenever Iraqi forces abandoned their posts and ran away from ISIS and they took hold of Mosul and various other places.
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“There was a real feeling of disgrace at the time.
“They’ve been working hard over this last two years to regain all of that ground that they lost.
“The victory parade is them righting the shame they felt of two or three years ago when they abandoned their posts and I think that’s important for them to do that.”
Mr Beattie said that IS fighters who had overran what was estimated to be nearly a third of Iraqi territory may be defeated but had not gone away.
The Upper Bann MLA from Portadown said: “I think IS will turn into an insurgency and insurgencies are notoriously difficult to defeat. I think that Iraq has got many battles ahead still. There will still be many terrorist activities taking place in Iraq.
“At one stage we were taking about IS being on the doorstep of Baghdad, we were talking about the collapse of Iraq.
“To stop that momentum, to consolidate yourself and go on the offensive to drive them back has taken huge efforts on behalf of the Iraqi nation and the coalition forces who have clearly helped them tactically and strategically.
“You can argue the case about victory parades – whether they are a good thing or a bad thing – but this is a case of national pride so I think they were right to hold a victory parade.”
Asked how significant the victory was in the global battle with IS, Mr Beattie said: “Any state which is viewed as a failed or disrupted state, which Iraq was for quite some time, to be able to secure its own ground within its own borders means that it denies international terrorist groups like Islamic State from setting up within that country – it’s incredibly important.
“We still have this ongoing issue in Syria, which becomes isolated by Iraq having secured its own borders.
“Syria becomes the issue now. If you can stabilise Syria and rid it of IS and get an up and coming free government then you’re going quite some way to stabilising the area.
“We may well be focusing on Iraq one minute and then Syria the next. Soon we may well be refocused on Palestine and Israel, and certainly we’re going to be focused on Libya.
“The whole region of north Africa that bleeds into the Middle East still remains extremely volatile.”