“I can’t help it,” Lola (Marlene Dietrich) sings languidly from the stage at the Blue Angel cabaret, bemoaning the inadvertently ruinous effect she has on men. Which somehow makes it worse — you destroyed my life, and you weren’t even trying?

One of the cinema’s great tales of romantic obsession, Josef von Sternberg’s 1930 “The Blue Angel” has been re-released for the first time on Blu-ray this week by Kino Classics in a two-disc edition. The discs feature both the German-language and English-language editions, which were shot simultaneously using the same cast, but the German-language version has been rarely seen in America.

The film charts the fall of Professor Rath (Emil Jannings), an arrogant professor at a boys’ school who delights in tormenting his young students — in one scene, he sticks a pencil in a frightened boy’s mouth to get him to properly pronounce “the” and not “ze.” This humiliation will be revisited tenfold upon Rath later.

One night, he follows his boys to the Blue Angel, where he’s transfixed by the figure of Lola, the star of the show, a coquettish vision in top hat and garters. I have to admit, I first knew of Dietrich primarily through Madeline Kahn’s hilarious send-up in “Blazing Saddles,” and she perfectly captures that offhand sexuality that Dietrich exudes from every pore.

The Professor is instantly smitten, and starts courting her. She reacts with amusement at this big, bluff figure reduced to a stammering schoolboy in her presence, but eventually seems to give in, and the two make an unlikely couple.

Then we move ahead four years to the film’s shocking third act. The Professor has now been debased into becoming a sad performing clown, a shell of his former self. Lola treats him with ill-disguised contempt. He has ruined his life, and what’s worth, the cabaret tour is coming back to the Professor’s hometown, where he will be forced to play the fool on stage in front of his old students and colleagues. The last scenes — of the disgraced Professor, literally with egg on his face, crowing madly before a laughing, jeering audience, are nightmarish.

Jannings takes the Professor on an incredible downward spiral — as contemptible as the arrogant Professor is in the early scenes, you feel genuine pity for him as he falls from grace. And Dietrich’s role is more complex than it first appears — she’s a femme fatale, but her motives remain veiled.

The extras on the Kino edition include side-by-side comparisons of the German and English versions for one early scene — they seem almost identical, although perhaps the English version is cut a little more crisply. But whatever version you choose to watch, “The Blue Angel” is a classic of world cinema that exudes its hypnotic power over 80 years later. It can’t help it.