"Borderline" was a big disappointment, given the expectations I had from the MacMurray-Trevor star duo. They played their roles gamely in this awkwardly scripted, boringly directed melodrama (with light comedy overtones). If you forget about the tedious, poorly motivated plot line, there are a few enjoyably light and playful scenes between the two stars (both of whom look great, especially Trevor). They have good chemistry, and the inevitable romance that interferes with their respective drug enforcement chores (only because each believes the other is a criminal), works, despite the lazy script development. The romance works so well, in fact, that the plot demand that MacMurray turn Trevor in seems pretty unbelievable.
On a minor level, "Borderline" is interesting for its mid-20th century Hollywood depiction of Mexico and Mexicans. Lots of stereotyping, primarily for questionable comic effect. I disagree with IMDb's characterization of speaking "Mexican" as a goof. It struck me as intentional. That's the way some people talked then (and the way some people still do).
On a minor level, "Borderline" is interesting for its mid-20th century Hollywood depiction of Mexico and Mexicans. Lots of stereotyping, primarily for questionable comic effect. I disagree with IMDb's characterization of speaking "Mexican" as a goof. It struck me as intentional. That's the way some people talked then (and the way some people still do).