The first duet album from Willie Nelson and Merle Haggard, 1983’s Pancho & Lefty, became an unlikely smash hit because of the duo’s rendition of the Townes Van Zandt title song. Seashores of Old Mexico is a more modest but also more intimate affair. A hushed atmosphere pervades the album. “Jimmy the Broom,” “Without You On My Side” and “Why Do I Have to Choose” are among the gentlest performances by these already very gentle singers. The versions of old chestnuts like “Yesterday” and “Silver Wings” might border on drowsiness, but there’s no denying the soft desolation of “Love Makes a Fool of Us All.” Haggard sings his verse as if his head is resting on the listener’s shoulder, as the backing track recedes to make room for a beautifully threadbare guitar solo from Nelson. As the music quiets almost to nothingness, Willie — in his honeyed, wrinkled way — sings the album’s single most beautiful line: “Dreams of forever / Are just words in a letter / When goodbye is all that they say / She packs up a few things / And slips out of her ring / And into the arms of a man twice her age.”