How we cite our quotes: All quotations are from North by Northwest.
Quote #1
THE PROFESSOR: War is hell, Mr. Thornhill, even when it's a cold one.
The spy business reached its height during the Cold War era, when wars were fought with intelligence and not weapons. The CIA conducted espionage activities around the globe and kept close eyes on their Eastern Bloc counterparts. The Professor tries to keep Thornhill in the game by appealing to his sense of patriotism.
Quote #2
THORNHILL: We're on top of the monument.
In case you didn't catch just how close Roger and Eve get to those big presidential heads, the hero, running for his life, reminds you. A lot hinges on the dash across the great presidents' heads in North by Northwest, and the climactic chase scene's monumental backdrop underscores just how much is at stake, making the chase, too, seem monumental as well as exciting.
In the years following the film's release, the Park Service had to shoo more and more visitors out of prohibited areas of the monument. But overall, the film brought lots of great publicity to the park; tourists still ask about the film when they visit Mount Rushmore. (Source)
Quote #3
THE PROFESSOR: Thank you, Sergeant.
VANDAMM: That wasn't very sporting, using real bullets.
The scheming Vandamm keeps up his characteristic sarcasm to the very end. These are the last words we'll hear him say after his capture by the Professor and police, and they emphasize the sudden switch from blanks to real bullets that takes place as North by Northwest approaches its conclusion. The sergeant who takes Leonard down just in time gets to shoot a firearm that's the genuine article. Lucky for the newlyweds-to-be and the whole free world.
Quote #4
THORNHILL: If you fellas can't lick the Vandamms without asking girls like her to bed down with them and fly away with them and probably never come back alive, maybe you better start learning to lose a few cold wars.
This is the closest anyone in North by Northwest comes to criticizing the Cold War strategies that provide the film with its context. Here Thornhill objects to the extremes that the Professor is using to gain information. But a statement from earlier in the film has already anticipated, and pretty much defused, Thornhill's objection.
Quote #5
REPORTER (in the agency meeting at headquarters): C'est la guerre.
Translation: Such is war. (Think "c'est la vie": that's life.) Some of the Professor's fellow agents—and, later on, Thornhill—object to the ruthlessness of the tactics that he relies on to foil Vandamm and protect the national interest. But for the Professor and his crew it's all in a day's work when you're in the midst of a Cold War.