Terrorism seems to have become almost the normal instrument of politics in depressingly many areas of the world Northern Ireland, Britain, Lebanon, Argentina. Americans often have a hard time understanding the passions behind these debates of death, and can only be grateful that the U.S. has remained largely immune from such anarchic eruptions. But a tiny band calling itself the Armed Forces of Puerto Rican Na tional Liberation (F.A.L.N.) has once again proved that a few obscure fanatics can produce flickers of unexpected terror even in the U.S.
Last week bombs went off at ten widely scattered targets within 40...