Is this cause and effect or compare and contrast? In 1968, when the Democratic Party held its convention in Chicago to select a presidential
candidate, the United States was at war in Vietnam. Thousands of Americans and
Vietnamese had died in the war, giving rise to a growing anti-war movement. President
Johnson, a Democrat, declined to run for reelection, in part because of the heavy
opposition to his conduct of the war. Just months before the convention, both Martin
Luther King Jr. and Robert Kennedy were assassinated, contributing to widespread
unrest. Anti-war protesters wanted the Democratic Party to oppose the war, but they
were excluded from the convention. This set off violent clashes between police and
protesters on Chicago streets. The violence at the convention captured the nation's
attention strengthened the peace movement, and led to reforms in the nominating
process.

Which organizational structure does this text primarily use?