They are not aiming to win all 50 states although several have come close, such as Richard Nixon inand Ronald Reagan ineach of whom won 49 states. Therefore, the least populous states, such as Alaska and Wyoming, send three members to Congress - two senators and one representative.
This is used for candidates who did not fulfill the legal requirements to be pre-listed on the voting ticket. Some states hold only primary elections, some hold only caucuses, and others use a combination of both.
Constitution also has two provisions that apply to all federal offices in general, not just the presidency. In general, primaries use secret ballots for voting.
All pledged delegates are then "released" and are able to switch their allegiance to a different candidate. It is also used by voters to express a distaste for the listed candidates, by writing in an alternative candidate for president such as Mickey Mouse or comedian Stephen Colbert whose application was voted down by the South Carolina Democratic Party.
Trump claims he is absolutely no threat. Like the general election, presidential caucuses or primaries are indirect elections. Which candidates appear on the voting ticket is determined through a legal process known as ballot access. And the first candidate to win enough states to get to electoral votes becomes the president.
Republican candidate Donald Trump won the popular vote in 30 states denoted in red to capture electoral votes plus 1 electoral vote from Maine's second congressional district.
Like any other election in the United States, the eligibility of an individual for voting is set out in the Constitution and regulated at state level.