"If...." has to be one of my favorite films. Words do not describe the power of this movie to provoke, and its images stay with you for life. This is what Lindsay Anderson wanted--from us--the audience. I will try not to repeat BFI's incredible text on this film, it really does nail what the film is about, and how and why it was made. Give it a read, it has a lot to offer.
As specific as the setting of this movie is, there is a universality to it that renders it eternal. This wasn't necessarily intentional. There are so few films that are this pure, and "If...." illustrates how unique the 1960s-1970s were for directors. It was a time when aspiring directors had an open window to leave their mark in ways they hadn't been able to since the 1920s. One can only hope that similar artistic freedoms are waiting around the corner....
Again, arbitrary pecking-orders are universal, which explains the wide acclaim for the film. It's very basic presentation of oppression and the inevitable reaction it creates in any era. It's realism and surrealism is sometimes expressed in the use of both black and white and color, making for a very dreamy experience.
There are countless films from the 1960s-70s that did this, and they aren't part of the public mind for a good reason: they were too topical, often too much of their time, and they aren't very good. Anderson never cops-out in this film, and offers no pat explanations. His film truly is "epic" in its thematic scope of the eternal human yearning for liberty, and also a big step for gay cinema in the UK, possibly a first in its depictions of homosexual relationships. It's also a great poetic work of cinema, and one of the greatest British films ever made.
It is a Nietzschean parable, rife with existential angst, and so much more. Anderson's "crusaders" are not very different from their tormentors, and, as strange as it may seem, there was a similar uprising at the Tonbridge School in 19th century Kent. Kipling even wrote indirectly of the event, and so the tale is closer to reality than one might think.
The real public school "rebels" went on to become vanguards of the British Empire, underscoring how rebellion is often more than it seems. Often, it's merely a "will to power." Thematically--and in his own experiences--the context of "If...." was a subject close to Lindsay Anderson's own life and his heart. Other than Ken Russell and Michael Powell, I cannot imagine a better British director.
After the student uprisings of May 1968, and the Chicago Democratic National Convention in August, the Tet offensive, the assassinations, the riots, the demonstrations, the divisions, the December release of this film in that explosive year must have been a real bombshell to Western audiences (and it definitely was in the UK). Adults should wish to be so scandalized again. This is the violence inherent in the system, expressed by a conservative. A movie can change one's life. Lindsay Anderson converted his dreams into celluloid.