Why did Ronald Reagan win the 1980 US presidential election?

Reagan's remarkable success resulted from Jimmy Carter's poor record and economic malaise, Reagan's personal charisma and a growing tide of conservatism in America.

The 1980 election came after the bleak 1970s  with Vietnam, Watergate, the oil crisis and general economic underperformance all contributing to a difficult term for Jimmy Carter between 1976-80. Staglation (high unemployment and high inflation) undermined the liberal economic consensus of Keynesianism which advocated high government spending and Reagan capitalised on dissatifaction with such policies by promoting smaller government policies. Indeed, Reagan used his excellent oratory skills in debates to highlight Carter's struggles on issues such as the economy and Iran, further helping his campaign. Lastly, the electorate was changing with the growing conservatism in America most vividly seen with the growth of the evangelical Christian vote as a strongly Republican bloc.

These trends and factors all enabled Reagan to successfully depict Carter and liberalism as failed, in contrast to a smaller government platform that appealed to an increasingly conservative electorate.