BERKELEY—Are our migrants heroes or opportunists?

Decidedly heroes, in composer Jimmy López’s view. He made a strong case for them in his evocative world premiere oratorio “Dreamers,” featuring a sensitive libretto by Nilo Cruz. With the amazing maestro Esa-Pekka Salonen conducting, the 41-minute oratorio was unreeled at Zellerbach Hall March 17.

“Dreamers” traces all migrants, from pre-history around the world, in an abstract story-telling. As it turns to the specific plight of the Dreamers and their followers across our frontiers today, it becomes highly emotional, in a way that few new works today are oriented. The gradual transition from detachment to keen involvement is brilliantly negotiated by López-Cruz with texts both English and Spanish. By the end, the solo soprano, often voicing a child making a hazardous  crossing with detention and isolation awaiting across the border, is immersed in anguish, anger and frustration, with the large chorus of some 90 echoing her phrases.

This is a magnetic, visceral work intertwined with the heated politics of today. Berkeley is an ideal locale to voice these sympathies, as this campus has a current enrollment of some 500 Dreamers, the name given to long-residing immigrant DACA youths who are in the US but stuck in a legal limbo of great uncertainty and threatened deportation. (‘Dreamers’ is a very misleading term for these Cal students; the academic pressure on one and all hardly allows idle time for lah-di-dah dreaming!)

The musical style of Peruvian-born López, a 40-year-old Berkeley Ph.D. grad, is tonal and post-Stravinskian, with strong rhythmic emphasis. The vocals are punctuated by surging orchestral thrusts led by the large percussion group. Indeed, the orchestra itself (London’s elite Philharmonia) was needlessly large.

The opus made a powerful impression, particularly with its gradual turn from impassiveness to bitterness over mistreatment of migrants.

Leading the performance March 17 were paired stars. Apart from the vigorous Principal Guest Conductor Salonen, who prepares his ensembles meticulously, the premiere featured the stunning spinto soprano Ana Maria Martinez from Puerto Rico, where neglected storm survivors embody yet another chapter of human despair.

Vocally, Martinez has a broad range, a high top, great projection and secure pitch. Her artistry unfolded lustrously as the oratorio’s emotional intensity accelerated. By the final curtain, “Dreamers” resonated like an operatic tragedy.

The combined choruses of Volti and UC Berkeley were effective, though the upstage placement dulled their impact. This premiere unleashed a four-minute ovation.

Love it or hate it, the oratorio explores the issue from the perspective of the dreamer-migrant eloquently, sympathetically, incisively. The challenge is to hear it not as a political manifesto but as a musical work that speaks from the heart, telling of “children smuggled out because they didn’t deserve to be killed” in their crime-torn land of origin.

The presentors at Cal Performances pulled out all the stops for their commission, offering a complimentary post-concert reception for all comers to meet the artists. “Dreamers” was also scheduled for Stanford University and,  later, the Houston Symphony.

On any other night, the headlines would have been about Salonen’s extraordinary leadership in the complete Stravinsky “Firebird” ballet music. This is a problematic, drawn-out piece that, for the first time, spoke to this listener with unique eloquence (Most orchestras prefer the concise subsequent chamber-orchestra revision of “Firebird,” only half as long but adding unique orchestral touches including the Kastchei “bang”). The crisp interpretation with ear-carressing incipits (i.e., starts) and countless dynamic gradations by Salonen and his virtuoso orchestra brought new meaning and articulation to this great example of orchestration and Eastern exoticism.

López’s oratorio premiere “Dreamers” at Cal Performances, Zellerbach Hall, Berkeley. To be available on CalPerformances.org/livestream till mid-April.  For CP info: (510) 642-9988, or go online.