IN THE LAST WEEK, Greek and Korean students have escalated their struggles for academic freedom, political democracy and human dignity to levels of heroism difficult for American students even to imagine. In both Greece and South Korea, military dictators have threatened to use massive military force to end student demonstrators' demands for free elections and civil liberties.

Both countries' people have learned by experience that when demonstrations fail, their leaders and participants, as well as any bystanders arrested by mistake, are likely to go to prison for a long time, to be tortured by their captors, and to have their careers and bones shattered by the military police. That students nevertheless persist in demanding justice and human rights should be a source of wonder and pride to students in this country and throughout the world.

But Americans can't take similar pride in the role their own government plays in Greece or Korea. In both countries, the United States is the principal supporter of the dictators. It sends them money and assistance which they use to make their control crueler and more complete. When the Greek government declared martial law on Sunday, the tanks it deployed against student demonstrators were American tanks, and the blood of those demonstrators killed fighting for democratic ideals reddens President Nixon's hands almost as deeply as the blood of Cambodian farmers killed by his bombers.

Thai students brought down their country's military dictatorship last month. If their counterparts elsewhere fail this week, it will be not because they are less brave--courage like theirs is a theme for romance or epic poetry--but because the United States, to its disgrace, arms their assassins.