As New York’s Saint Patrick’s Day parade steps off this morning, it’s not only the Irish who are smiling. At least, not only those we typically think of as Irish. Over in the Democratic presidential race, there is the man we referred to in a May 3, 2007, editorial as “Barack O’Bama,” whose great-great-great-great grandfather was Joseph Kearney, a shoemaker from Moneygall, County Offaly, Ireland, who lived from 1794 to 1861 and arrived in New York as an immigrant in 1850. We noted at the time that while much has been made of Mr. Obama’s Kenyan roots, little has been made of his Irish ancestry.

Senator Obama is facing off against Senator Clinton, who might be labeled (D-Dublin) for all the emphasis she has lately been putting on Irish issues. A press release issued over the weekend by the Clinton campaign reports that Mrs. Clinton “traveled to Northern Ireland seven times between 1995 and 2004,” and it quotes the president of the political wing of the Irish Republican Army, Gerry Adams, as saying, “Senator Clinton played an important role in the peace process…I met the senator on many occasions when she was First Lady, and subsequently when she became a senator for New York State. I always found her to be extremely well informed on the issues.”

As for the Republican, John McCain is Irish, too, and has won support in the Irish community for his leadership on the immigration issue. His campaign store is featuring “Irish for McCain” t-shirts and buttons. He also made a newsworthy speech in 2005 to the American Ireland Fund, with Gerry Adams in attendance. “There is simply no place in a democracy for a private army engaged in illegal activity. It is not enough for Sinn Fein to cut its ties to the IRA. The political leadership should join the call for the IRA to disarm, demobilize, and disband, once and for all. Stealing from banks and slaying men in the streets to settle personal grievances are not the acts of freedom fighters. They are the work of a small minority trying to hold back the forces of history and democracy, and they hurt the very people for whom they claim to fight,” Mr. McCain said.

Meanwhile, the Daily News’s Joe Mahoney reported in February that a DNA test on David Paterson — then the lieutenant governor of New York, now about to become governor — showed that Mr. Paterson’s maternal grandmother was Irish. “‘I might be connected to you,’ Paterson joked to a reporter with family roots in the Emerald Isle,” the News reported. There’s a temptation to dismiss some of this as goofy political pandering, and in some cases that may be an element of it. But the broader point is that America’s immigrant diversity is a source of strength that enriches the American idea.