WHEN STING LEFT the Police to pursue a solo career, the photogenic, multiplatinum superstar could have done whatever he wanted.

So one has to admire him for pushing his songwriting into new political and psychological territory and for stretching his music to include jazz and ethnic influences. As admirable as his ambitions are, however, his actual achievements have been relatively modest. Sure, his two solo albums have their undeniable pleasures, but they fall far short of the best songwriting and jazz-rock experiments going on elsewhere.

Sting's second solo album, " . . . Nothing Like the Sun," once again finds him playing with young jazz all-stars. They play beautifully, especially guitarist Hiram Bullock on "Little Wing" and saxophonist Branford Marsalis on "They Dance Alone," but the result is very tasteful art-rock rather than any true integration of jazz and rock. Sting has lengthened and loosened his songwriting style to incorporate moody atmospherics but hasn't allowed enough room for real jazz improvisation.

In the process, he has sacrificed his most obvious asset: his knack for melodic and rhythmic pop hooks. Moreover, he has highlighted his most obvious weakness: his lyrics. Especially when he writes about the power of women to redeem a man's life, he lapses into romanticized abstractions.

Surely it's no coincidence that the four strongest songs on this album were inspired by other people's experiences or other people's music: "They Dance Alone" is a dazzling seven-minute Andean music suite for Latin America's political prisoners; "Fragile" is a subdued eulogy for Contra victim Ben Linder; "Little Wing" is an elegant reworking of the Jimi Hendrix song; and "Secret Marriage" is a stark duet based on a Hans Eisler melody. STING -- ". . . Nothing Like the Sun" (A&M SP 6402). Appearing Saturday at the Patriot Center.