An Irish bandleader and an American guitarist walk into a bar in Havana….

Sounds like the setup for an ethnic joke, but it’s actually the genesis of San Patricio, the new album by the Chieftains and Ry Cooder. Back in 1996, the Chieftains were in Cuba’s capital to record Santiago. After a session, their leader, Paddy Moloney, and Cooder were in that bar throwing back a few when the Irishman brought up the story of the San Patricio Battalion, a group of Irish soldiers who defected from the US Army to fight for Mexico during the Mexican-American War.

Cooder “told me I had to record an album about them and he wanted to be involved”, Moloney said in a March 2010 interview with The Irish Times. “So that’s when we really clicked on this project.”

Moloney and Cooder already had worked together, on the Chieftains’ 1995 album The Long Black Veil, and Cooder was a session man on Santiago. But those efforts were just a dry run for San Patricio, an ambitious and wholly successful collaboration between the five-decades-old Irish band, Cooder, and a host of Mexican and Mexican-American artists.

Cooder appears on only four of the 17 tracks, but he’s the record’s co-producer (with Moloney) and its guiding spirit. San Patricio, like Cooder’s superb 2005 album Chavez Ravine, is a kind of aural documentary that recounts a piece of hidden history, with a leftist political slant. Chavez Ravine evoked the eponymous Mexican-American community in Los Angeles destroyed during the 1950s by real estate development. The story of the San Patricio Battalion likewise is one of loss, even tragedy.

In the 1840s, Irish immigrant men escaped the Potato Famine only to find that they were to be cannon fodder in America’s imperialist war against Mexico. Says Paddy Moloney in the San Patricio album notes, “They got off the boat at Ellis Island and then, ‘here’s a gun and go down there and shoot the Mexicans.’ That didn’t go down well with Catholics, as they were shootin’ other Catholics.”

These reluctant soldiers were mistreated by their officers and discriminated against because of their religion. Led by Captain John Riley, nearly 200 deserted, heeding appeals from Mexico to join their co-religionists in battling the Manifest Destiny-obsessed Yankees. They formed the San Patricio Battalion, fighting for Mexico under their own green banner.

Though they fought fiercely and inflicted some serious damage on American troops, most members of the battalion were killed or captured, with a number of them court-martialed and hanged. Dozens had a “D” for “deserter” branded on their cheeks.

The San Patricios were largely forgotten both in Ireland and Mexico, until the Irish and Mexican governments held a joint ceremony in Mexico City in 1997 to commemorate their contributions.

But if the San Patricios’ story is downbeat, the mix of Mexican and Irish sounds that Moloney and Cooder have cooked up is anything but. Some tracks balance Ireland and Mexico; fiddles and harps, played throughout the album, are common to both musical cultures. Two numbers are echt-Irish: the ethereal “Lullaby for the Dead”, sung by Moya Brennan of Clannad, and “Sailing to Mexico”, a spirited waltz featuring the Spanish piper Carlos Núñez. Fans of Paddy Moloney’s work on Uilleann pipes, tin whistle, and bodhrán won’t be disappointed.

But like the San Patricios themselves, Moloney and the Chieftains mostly follow the Mexicans’ lead. Ireland, in fact, starts to recede not long into the album, as the regional styles of Mexico—rancheras, boleros, sones, and norteño music—become dominant. The Irish instrumentation mainly embellishes the sounds of the Mexican guitars, accordions, bajo sexto, trumpets, and percussion.

The album’s roster of distinguished guests includes Linda Ronstadt, backed by Cooder on the ballad “A la Orilla de un Palmar”; the Mexican-American singer Lila Downs, lustily tearing through two numbers, “El Relámpago” and “La Iguana”; the great ranchera singer Chavela Vargas, now 92, an emotional powerhouse on “Luz de Luna”; the veteran norteño band Los Tigres del Norte backed by Cooder on the waltz “Canción Mixteca”; and three traditional groups, Los Folkloristas, Los Cenzontles, and Los Camperos de Valles.

Besides Cooder, the gringos include Van Dyke Parks, contributing piano and accordion to an instrumental version of “Canción Mixteca”, saxophonist Paul Cohen (Lila Downs’ husband and collaborator), and actor Liam Neeson, who narrates “March to Battle”. (“We are the San Patricios, a brave and gallant band. There’ll be no white flag flying within this green command.”) Cooder, in addition to his numbers with Ronstadt, Los Tigres, and Parks, performs his composition “The Sands of Mexico”, singing and playing guitar, laud, timbales, and piano.

Global fusion isn’t new to the Chieftains. They’ve worked with Spanish musicians and Chinese folk bands, as well as rock, pop, and country eminences like Mick Jagger, Sting, Ziggy Marley, Lyle Lovett, and Alison Kraus.

San Patricio, though, is their most accomplished cross-cultural project to date. Cooder has recorded with Mexican, Malian, Indian, and Hawaiian artists, and of course with the elderly Cubans whose careers he helped revive with the Buena Vista Social Club. That album, released in 1996, remains one of the top-selling titles in so-called “world music”.

As much as I’ve appreciated those pairings, and as impressed as I am by San Patricio, I’d love to see Cooder tap another culture—his own Italian roots. (His mother’s family immigrated to California from the northern region of Emilia-Romagna.) Italy boasts a rich and diverse folk music tradition, from the Alps to Sicily, that has absorbed influences from the various cultures that have populated the peninsula and its islands—French, Spanish, Greek, Arab and North African.

If that’s not enough to catch Cooder’s ear, there are the politics: the Italian repertoire is full of rebel music, songs of anarchism and socialism, workers’ revolts, and World War II partisan fighters. And smart, genre-bending Italian cantautori (singer-songwriters) like Vinicio Capossela and Carmen Consoli would make great collaborators.

An Italian-American Social Club—Think about it, Ry!