In United States politics and government, the term presidential nominee has two distinct meanings.

The first is the person chosen by the primary voter

Primary election

A primary election is an election in which party members or voters select candidates for a subsequent election. Primary elections are one means by which a political party nominates candidates for the next general election....

s and caucus

Caucus

A caucus is a meeting of supporters or members of a political party or movement, especially in the United States and Canada. As the use of the term has been expanded the exact definition has come to vary among political cultures.-Origin of the term:...

-goers of a political party to be the party's nominee for President of the United States

President of the United States

The President of the United States of America is the head of state and head of government of the United States. The president leads the executive branch of the federal government and is the commander-in-chief of the United States Armed Forces....

. The main nominees for the presidential election 2008 were Democrat

Democratic Party (United States)

The Democratic Party is one of two major contemporary political parties in the United States, along with the Republican Party. The party's socially liberal and progressive platform is largely considered center-left in the U.S. political spectrum. The party has the lengthiest record of continuous...

 Barack Obama

Barack Obama

Barack Hussein Obama II is the 44th and current President of the United States. He is the first African American to hold the office. Obama previously served as a United States Senator from Illinois, from January 2005 until he resigned following his victory in the 2008 presidential election.Born in...

 and Republican

Republican Party (United States)

The Republican Party is one of the two major contemporary political parties in the United States, along with the Democratic Party. Founded by anti-slavery expansion activists in 1854, it is often called the GOP . The party's platform generally reflects American conservatism in the U.S...

 John McCain

John McCain

John Sidney McCain III is the senior United States Senator from Arizona. He was the Republican nominee for president in the 2008 United States election....

.

The second meaning is someone nominated by the sitting U.S. President for appointment to any of numerous governmental positions, under the President's executive authority

Executive (government)

Executive branch of Government is the part of government that has sole authority and responsibility for the daily administration of the state bureaucracy. The division of power into separate branches of government is central to the idea of the separation of powers.In many countries, the term...

, subject to the approval of Congress.