A landslide victory is an electoral victory in a political system, when one candidate or party receives an overwhelming majority of the votes or seats in the elected body, thus all but utterly eliminating the opponents.
A landslide, also known as a landslip, is a form of mass wasting that includes a wide range of ground movements, such as rockfalls, deep failure of slopes, and shallow debris flows.
TV Talking Heads Confidently Predict a ‘Landslide’ Victory for Hillary by National Review
The winning party has reached more voters than usual, and a landslide victory is often seen in hindsight as a turning point in people's views on political matters.
TRUMP's LANDSLIDE VICTORY: Hillary Stole Election and STOLE Trump’s Mandate. by MLordandGod
Part of the reason for a landslide victory is sometimes a bandwagon effect, as a significant number of people may decide to vote for the party which is in the lead in the pre-election opinion polls, regardless of its politics.
The bandwagon effect is a phenomenon whereby the rate of uptake of beliefs, ideas, fads and trends increases the more that they have already been adopted by others.
An election is a formal decision-making process by which a population chooses an individual to hold public office.
Politics is the process of making decisions applying to all members of each group.
The term is borrowed from geology, where a landslide takes almost everything with it on its way.