The Democratic Party has its roots in the Democratic-Republican Party founded in 1792 by Thomas Jefferson and James Madison. They and their supporters -- including "yeoman farmers" -- opposed Alexander Hamilton's Federalist Party fiscal policies, which they said favored banks and wealthier Americans. Jefferson became the first Democratic presidential candidate when he ran for office in 1796, when he lost to John Adams and became Adams' vice president. He became the third president in the next election and served two terms starting in 1801.

Slideshow: Democrats In History

Other icons of the party, including former presidents Franklin D. Roosevelt and John F. Kennedy, continued with Jefferson's identification with struggling factions within America. Roosevelt's "New Deal" was a swift counteract to the Great Depression, which left millions of Americans in economic ruin. Kennedy's "New Frontier" program provided housing for middle and low-income families, increased the national minimum wage introduced under Roosevelt in 1938 and promoted civil rights. The Civil Rights Act of 1964 was signed into law by Democratic President Lyndon Johnson.

Still, the Democrats have faced strong opposition to some legislative initiatives. The party's support of civil rights in the 1960s cost it support in southern states. Former President Ronald Reagan effectively tagged Democrats in the 1980s as a party of big-government tax-and-spenders. The party lost their long-held majority in both houses of Congress in 1994, regaining it in 2006. But the Democrat's support of abortion rights, gun control, progressive taxation, stem-cell research and same-sex marriage, and its opposition to the Iraq war, continue to generate strong opposition, especially from conservative Republicans.

When the Democrats regained control of Congress in 2006, they made history by electing Rep. Nancy Pelosi, of California, the first female speaker of the House of Representatives. In September, when party delegates convened in Denver, they formally nominated Sen. Barack Obama as the first black candidate from either major party to be the party's nominee for the White House.