Glossary: US elections
What is the difference between Medicare and Medicaid? What are blue dogs and red states? These are just a few of the many well-used but often misunderstood terms in US politics.
Reagan Democrat Working-class Democratic voter who defected from the party to vote for Republican candidate Ronald Reagan in the 1980 and 1984 presidential elections.
The term is also used these days to denote moderate Democrats who are more conservative than other Democrats on issues such as national security or immigration.
Red state A state where people tend to vote for the Republican Party.
Roe v Wade The landmark 1973 Supreme Court judgement that prohibited states from banning abortion.
The court's ruling was based on the concept that a woman's right to terminate her pregnancy came under the freedom of personal choice in family matters as protected by the Fourteenth Amendment.
The decision remains one of the most controversial ever made by the Supreme Court.
While states are prohibited from barring abortion outright, they have been allowed under subsequent Supreme Court rulings to restrict certain types of abortion and place often onerous requirements on doctors who provide abortion and women seeking them.
Running Mate The presidential nominee's candidate for the vice-presidency.
Second Amendment The so-called right to bear arms amendment to the US constitution, ratified in 1791.
The text reads: "A well-regulated militia being necessary to the protection of a free state, the right of the people to keep and bear arms shall not be infringed."
The wording is open to interpretation and as a result it has become the focus of fierce debate between supporters and opponents of gun control.
Gun control opponents such as the National Rifle Association argue that the amendment gives Americans the constitutional right to bear arms free from any form of government control. But advocates of gun control argue the amendment was only written to guarantee the right to bear arms as part of a collective militia, and say states and municipalities should be able to restrict gun ownership and use.
Senate The upper house of Congress, although members of the other house - the House of Representatives - traditionally regard it as an equal body.
The Senate has 100 elected members, two from each state, serving six-year terms with one-third of the seats coming up for election every two years. The vice-president serves as the presiding officer over the Senate, although he or she does not serve on any committees and is restricted to voting only in the event of a tie.
Senate Majority Leader The leader of the majority party in the Senate, and the most powerful member of the upper house of Congress.
He or she controls the daily legislative programme and decides on the time allowed for debates.
Senate Minority Leader The leader of the minority party in the Senate.
He or she acts as a figurehead for the minority party in the Senate, articulating its policy positions and attempting to deliver its legislative priorities.
Senator Member of the Senate, the upper house of Congress. Each US state has two (a junior and a senior senator, distinguished by length of service).
Before Barack Obama, the last time a senator was directly elected to the White House was in 1960, when John F Kennedy won the presidency.
Speaker of the House The leader of the majority party in the House of Representatives - not to be confused with the House Majority Leader.
The House Speaker has a dual role as both the leader of his or her party in the House, and as the presiding officer in the chamber, with responsibility for controlling debate and setting the legislative agenda.
Under the terms of the Presidential Succession Act of 1947, the speaker is the second in line to the presidency after the vice-president.
Stump speech A candidate's routine speech outlining his or her core campaign message.
The speech can be tailored to suit specific audiences and may evolve over the course of the campaign.
The phrase stems from the days when candidates would make speeches standing on tree stumps. Campaigning politicians are still said to be on the stump.
Supermajority The vote margin of two-thirds or three-quarters of the quorum, as opposed to a simple majority of 50% plus one.
For example, for an amendment to be added to the US constitution, it must be approved by a supermajority of two-thirds in both houses of Congress and the legislatures of three fourths of the states.
In the Senate, a supermajority of 60% is required to end a debate on a bill. In recent years, the minority party party has forced the senate to require a supermajority to pass almost all substantive legislation, contributing to political gridlock in Washington.
That gridlock is expected to be an issue in the 2012 presidential campaign, with Mr Obama and the Democrats accusing Republicans of using parliamentary manoeuvres to obstruct progress.
SuperPac A category of independent political action group established by the Citizens United Supreme Court decision that is allowed to accept and spend unlimited amounts of corporate, individual or union cash on behalf of a candidate, often without disclosing its sources.
SuperPacs are barred from co-ordinating their spending - usually on advertising - with the candidates they support, but some say they in essence operate as shadow campaign committees. See entries on Citizens United and soft money.
Super Tuesday The day in the campaign calendar, usually in February or early March of an election year, when a large number of states hold primary elections.
In 2012, Super Tuesday will be on 6 March.
The first Super Tuesday occurred in the 1988 campaign, when southern state party officials hoped that by holding their votes on the same day they would increase the influence of the South and downplay the importance of the earlier New Hampshire primaries and Iowa caucuses.
Since then a number of other states have chosen to hold their primaries on the same day, including California.
Swift-boating The name given by Democrats to the tactic of unfairly attacking or smearing a candidate, often with half-truths.
The term refers to the series of anti-John Kerry adverts aired in the run-up to the 2004 presidential election by an ostensibly independent group of supporters of George W Bush called the Swift Boat Veterans for Truth.
The adverts featured veterans who - like Mr Kerry - served on naval craft known as swift boats in Vietnam and who were critical of Mr Kerry's record in the war. The Kerry campaign said they unfairly distorted his war record.
Swing states States in which the electorate is relatively evenly split between Republicans and Democrats, making them targets for aggressive campaigning by both sides.
In recent elections, the most important swing states were Florida, Ohio and Pennsylvania. Those have a high number of electoral votes, making them prime battlegrounds during the election.
The list of swing states changes with their demographics.
In the 2008 election, for instance, historically Republican Virginia and North Carolina voted for Barack Obama, anticipating their status as hard-fought swing states in 2012.
Others that were close in previous elections, like Iowa and New Mexico, appear to be solidly Democratic. (See Battleground State)
Tea Party A populist conservative movement known for its uncompromising stance on fiscal issues, its disdain for Mr Obama, and the stridency of its rhetoric.
The Tea Party movement arose in spring 2009 in opposition to Mr Obama's agenda, in particular his struggle to reform the US healthcare system.
Its primary demands are drastic cuts in government spending and taxes.
The movement's record of political success has been mixed.
Tea Party activists, supported with funding and organising assistance from well-heeled conservative backers, elected a class of fiscal conservative freshmen Republicans to the House of Representatives in 2010.
But their insistence on ideological purity has yielded some Republican candidates who are unpalatable to the broader electorate.
And Democrats blame the Tea Party movement for much of the Republican Party's inability and unwillingness to compromise on tax increases they say are needed to reduce the US budget deficit.
It is named for a series of colonial-era protests in which American revolutionaries dumped British tea into the sea to protest against a tea tax.
Third-party candidate A candidate who does not belong to one of the two main US political parties, the Republicans or the Democrats.
Examples of third-party candidates who ran in 2008 were independent Ralph Nader and Bob Barr, the Libertarian candidate.
No third-party candidate has ever won the presidency, but they may have influenced the result in 1992, when Ross Perot took votes away from incumbent George HW Bush and helped Bill Clinton to victory. In 2000, Green Party candidate Ralph Nader is believed to have siphoned votes from Democrat Al Gore.
Vice-President The presiding officer of the US Senate and the person who assumes the office of the president in the event of the resignation, removal, incapacitation or death of the incumbent president.
The vice-president only casts a vote in the Senate in the event of a tie.
Although those are the only duties the US constitution enumerates for the office, the vice-president can amass significant informal power in his capacity as an advisor to the president.
Early vice-presidents had little else in the way of official responsibilities.
In 1885 Woodrow Wilson, who would later become president, commented that there was "little to be said about the vice-president... His importance consists in the fact that he may cease to be vice-president".
In recent years, though, vice-presidents have taken on an increasingly prominent role managing a range of high-profile foreign and domestic policy programmes.
Dick Cheney, who served under George W Bush, is considered the most powerful vice-president in US history.
Wedge issue An issue on which a candidate campaigns in order to divide factions within his opponent's supporter base.
For example, in 2004 Republicans proposed same-sex marriage bans in more than a dozen states and Republican candidates loudly trumpeted their support.
The subsequent referenda were aimed at attracting voters who support the Democrats on most economic issues but who feel strongly about social issues.
Conversely, Democrats might highlight their more liberal position on abortion, in an attempt to win over pro-choice Republicans.
Wonk A political figure or pundit seen as having a studied and detailed command of public policy.