Conservative peer Lord Hayward will introduce a bill on equal marriage in Northern Ireland in the House of Lords on Tuesday, with Labour MP Conor McGinn set to introduce an identical bill in the Commons on Wednesday.
It's a significant demonstration of cross-party support and there's every prospect that it reflects the will of a majority in both Houses of Parliament.
In 2015, a majority in the Northern Ireland Assembly voted to support equal marriage, but was blocked when the DUP invoked the petitition of concern mechanism, which requires legislation to have majority support in both communities.
Following last year's assembly election, the DUP no longer has the votes to invoke a petition of concern on its own, but the issue has not been tested because of the breakdown of devolution.
The DUP's confidence and supply agreement with the Conservatives represents powerful leverage at Westminster, but its limits have already been shown on social policy.
As the Belfast News Letter's Sam McBride told a debate in Hammersmith last month, DUP indifference to metropolitan opinion received a sharp jolt last year when an amendment by Stella Creasy ensured that Northern Ireland women would get access to NHS abortions in Britain.
Northern Ireland Secretary Karen Bradley, who herself voted for equal marriage in Britain, has said that the Government will allow a free vote.
That will probably ensure a majority in the commons, though a private members bill might still face filibustering from the DUP and its allies. That would set in stone the DUP's reactionary image in Britain.
It's an interesting dilemma for DUP MPs. Some may privately be glad to be shot of responsibility for the issue. Others may have religious convictions of their own or concerns about TUV inroads in their constituencies.
With the ongoing decay of devolved institutions, there will be increasing attempts to deal with other logjam issues via Westminster. The Labour Party last week raised the Government's disgraceful use of inquest funding as a political bargaining chip, for example.
Such legacy issues are likely to find fewer friends on the Tory backbenches than equal marriage. Nevertheless, if some urgent issues can be resolved via Westminster, it will help to clear the decks for the renewed negotiation on devolution that will have to come sooner or later.