Presumptive nominee is a term used when a person or organization believes that the nomination in inevitable.
The act of being a candidate in a race is called a candidacy.
"Candidate" is a derivative of the Latin "candida" (white). In Ancient Rome, people running for political office would usually wear togas chalked and bleached to be bright white at speeches, debates, conventions, and other public functions.
Candidates are either incumbents, if they are already serving in the office for which they are seeking re-election, challengers, they are seeking to unseat an incumbent, or are simply candidates for an open seat, an elective office for which no incumbent is seeking re-election.
In the context of elections for public office in a direct democracy, a candidate can be nominated by any eligible person -- and if parliamentary procedures are used, the nomination has to be seconded, i.e., receive agreement from a second person.
In some non-partisan representative systems (e.g., administrative elections of the Bahá'í Faith), no nominations (or campaigning, electioneering, etc.) take place at all, with voters free to choose any person at the time of voting--with some possible exceptions such as through a minimum age requirement--in the jurisdiction. In such cases, it is not required (or even possible) that the members of the electorate be familiar with all of the eligible persons in their area, though such systems may involve indirect elections at larger geographic levels to ensure that some first-hand familiarity among potential electees can exist at these levels (i.e., among the elected delegates).
A person may also be directly nominated for a post without having to be elected.
A candidate may be considered a presumptive nominee after all other major competitors have dropped out and it is considered unlikely that the candidate will withdraw, be usurped, or be otherwise removed from the race. Alternatively, in presidential elections, a candidate may be deemed the presumptive nominee after having accumulated enough delegate commitments through the primary elections and caucuses to be assured of the eventual nomination at the convention.
In the U.S. presidential elections, the selection of delegates has been increasingly shifted earlier in the process to produce a presumptive nominee as early as possible, even in the presence of many strong candidates. The rise of Super Tuesday in the 1980s has led to the emergence of a presumptive nominee in both major parties by early March in all recent elections with the exception of 2008, when a spirited contest between Democratic candidates Hillary Rodham Clinton and Barack Obama made it impossible for Obama to secure enough delegates and become the presumptive nominee until early June. Al Gore and George W. Bush were the presumptive nominees of their respective parties after Super Tuesday in 2000, and John Kerry was the presumptive nominee for the Democratic Party in 2004.
A sitting President of the United States who is running for re-election will often be the presumptive nominee from the start of the nominating process: recent examples include Ronald Reagan in 1984, Bill Clinton in 1996, and George W. Bush in 2004. However, a strong challenger or weak president can negate that status: examples in recent history include President Gerald Ford, who faced a challenge from Reagan in 1976 and President Jimmy Carter, challenged by Ted Kennedy in 1980.
John McCain is the nominee for the Republican party in the 2008 United States presidential election. McCain was formally nominated at the Republican National Convention. Barack Obama is the nominee for the Democratic party in the 2008 United States presidential election. He formally became the nominee when Hillary Clinton acclimated at the Deomcratic National Convention on August 27, 2008.