In the American electoral system, a primary election is an
election that determines the nominee for each political party,
who then competes for the office in the general election. A
presidential primary is a state election that picks the
delegates committed to nominate particular candidates for
president of the United States. A presidential caucus, as in
Iowa, requires voters to meet together for several hours in
face-to-face meetings that select county delegates, who
eventually pick the delegates to the national convention. No
other country uses primaries; they choose their candidates in
party conventions. Primaries were introduced in the Progressive
Era in the early 20th century to weaken the power of bosses and
make the system more democratic. In presidential elections, they
became important starting in 1952, when the first-in-the-nation
New Hampshire Primary helped give Dwight D. Eisenhower the
Republican nomination, and knocked Harry S. Truman out of the
Democratic race because of his poor showing. In 19