You might think it would be hard to find a Catholic-Protestant issue as far as Iraq is concerned but in the crucial debate on February 25th all the unionist MPs present voted for Tony Blair's motion declaring this to be Iraq's final opportunity to disarm, writes Steven King.
The SDLP MPs, unusually, were all in attendance and joined the Labour left, the Liberals, a few Tories and the other nationalists in the "rebel" lobby. Sinn Féin, while not yet attending Westminster, is, of course, in the vanguard of the Irish anti-war movement.
Last week's vote did not give expression to the diversity of unionist views on the current international crisis but would any member of Dáil Éireann - even Michael McDowell - have delivered as robust a defence of President Bush as David Trimble did, deprecating the "false caricature" presented of him?
Broadly, to many unionists George Bush appears a remarkably sympathetic figure. Not only do his Ulster roots count for him but his rugged, unaffected image finds more favour than that of Bill "Slick Willy" Clinton.
This is, after all, a born-again, Bible Belt, coffee-drinking President who is devoted to his wife and who really does pray.
While some of these characteristics are just as equally a turn-off for many Irish nationalists - and noting Bush's infamous campaign visit to Bob Jones University, an Ian Paisley hang-out - would Jack Kennedy's response to the current situation really have been so different?
Of course, not all reactions are derived through an ethnic prism but in 2001 you could tell the unionist-owned cars at Stormont by their Bush-Cheney bumper stickers. If Bill Clinton never strayed from the substance of the Good Friday deal, the lasting image was of the hugs for Gerry Adams and Martin McGuinness in Dublin. In the last phase of the Clinton presidency, the even-handed approach towards choreography of events in Ireland was quite lost.
Calculating a Gore presidency might mean more of the same, unionists took a benign view of a Republican victory. Unlike Clinton, who admitted there was an electoral consideration behind his input to the peace process, Bush seemed to be more interested in courting Cuban votes than Irish-American ones. Interestingly, one Cuban-American Congressman was spitting blood earlier this month, alleging that Fidel Castro hosted IRA training camps for Colombian FARC narco-terrorists.
That is far from saying that the "Bushies" have ideological hegemony within unionism. There is a certain kind of unionist who resents American "interference" in Northern affairs per se. You scratch our backs and we will scratch yours is their attitude; support our war on terror and we will support yours.
This kind of unionist cannot be persuaded to march against war even if the slogan "Ulster Says No. . .To War In Iraq" was meant to tempt him outdoors. He cannot bear to line up with Sinn Féin and its hypocrisy either - for peaceful disarmament by Saddam, but not yet by the IRA.
The anti-war rallies were a Europe-wide phenomenon. What was remarkable, though, was that they were so large in Ireland, the European country most comingled with the United States, the country you might expect to have most understanding of American post-9/11 opinion.
So if unionist opinion broadly mirrors the divisions in the UK generally, Northern nationalist opinion is almost homogeneous, perhaps reflecting the neutrality of the State they aspire to join and the Vatican's very public scepticism. Few of the Ulster soldiers in the Gulf come from the nationalist community while the not insignificant number from the Republic serving there in the Irish Guards and the Royal Irish Regiment might as well be invisible.
Northern nationalists - never keen on "English" wars since Redmondism became discredited - take a Kantian view of the world which assumes that mankind, even Saddam, is fundamentally benevolent and will respond to unilateralist gestures of goodwill. Northern Protestantism, deeply influenced by Calvinism as it is, takes a darker view of human nature.
Nor would the anti-war movement's identification with the Palestinian cause likely endear it to unionists. The Israeli flags and "Go On Sharon" graffiti in loyalist areas, mirroring republicans' Palestinian flags and "IRA=PLO=ANC" murals, are now legendary. Settler communities stick together, particularly those in states created by partition. Nor has unionism ever been tainted by the anti-Semitism that these days disguises itself as anti-Zionism. At the same time as the Limerick "pogrom" of 1904, Belfast had a Jewish Lord Mayor, after all.
So, to David Trimble, Saddam is not a socialist but "a crude, anti-Semitic nationalist". He has some cause to feel aggrieved that despite his staunch support for US policy, including regime change in Baghdad, some prominent Americans still seem to adopt a "six of one, half-a-dozen of the other" attitude to the Northern Ireland peace process. There is not even the sense that Mr Blair's position - that the IRA's continued existence "totally justifies" unionists' refusal to share power with Sinn Féin - is always supported wholeheartedly.
Those Irish politicians in Washington this week will find the St Patrick's Day events overshadowed by impending war with Iraq. Nevertheless, there continues to be an interaction between the two issues. American and British leaders would do well to remember that the agreement will not survive if the ordinary unionist voter becomes convinced they have a double standard on weapons of mass destruction.
Dr Steven King is political adviser to David Trimble.