The Taoiseach has said the DUP's objecting the Brexit deal, because it would rather maintain the union than have the best of both worlds.
Leo Varadkar described them as hard-line unionists, as a Dáil debate on the proposed Brexit text began.
TDs are likely to vote this evening to support the text negotiated between the EU and UK.
Earlier, Mr Varadkar hit out at the DUP - saying he won't be able to convince Arlene Foster that the deal is the best one for Northern Ireland.
"But that totally misunderstands her view - it's not the best of both worlds that the DUP wants.
"The DUP holds very firm to this view that the most important thing is the integrity of the Unied Kingdom, the integrity of the precious union.
"And if that means a lesser-world, that's acceptable - provided that the integrity of the union is upheld".
Theresa May and Jean Claude Juncker
Meanwhile the European Commission President and Theresa May are said to have made "very good progress" during talks about Brexit in Brussels.
The British Prime Minister's been meeting Jean Claude Juncker to discuss the UK's future relationship after it leaves the EU.
She remains under pressure from her own MPs tonight, many who want changes to her draft agreement.