The rise conservatism embodied in the candidacy of Ronald Reagan should be examined in light of events dating to the mid-1970s.
In the wake of the end of the Vietnam War, and with the domestic political turmoil still fresh from the war's divisiveness and from the Watergate scandal, the country was deeply split along ideological lines. Even within the Republican Party, conservatives were deeply divided between moderates and those further to the right. This division within the party was embodied in the 1976 nomination fight between President Gerald Ford, a noted moderate, and the more conservative figure of Ronald Reagan, a battle won by Ford.
The election of Jimmy Carter can be considered an impetus in the rise of conservatism that occurred during his presidency. Another factor was the growing military strength of the Soviet Union and the latter's increasing assertiveness in its conduct of foreign policy. President Carter's domestic and foreign policies were seen by many Americans as ineffectual, although well-intentioned. Carter's emphasis on human rights as the principal component of his foreign policy initiatives was seen as undermining autocratic U.S. allies in Latin America while disruptive of U.S.-Soviet relations. While the focus on human rights was certainly warranted in terms of the human rights records of both Latin American dictators friendly to the United States and of the Soviet Union, it provided a poor basis upon which to handle the broader issue of Cold War politics.
The domestic economy of the United States was also in poor condition, as the previous Ford Administration's efforts at bringing inflation under control were followed by the difficulties encountered by the Carter Administration, another important factor in the rise of conservatism. Compounding the economic problems during the Carter years was the energy crisis of the late 1970s, which saw motorists lining up for increasingly scarce and increasingly more expensive gasoline.
Economic problems were intertwined with foreign policy crises. The Iranian Revolution of 1979, saw the rise to power of virulently anti-U.S. religious clerics angered over U.S. support for the deposed Shah. Iran being a major exporter of petroleum, the impact of the revolution on the U.S. economy was profound. The fact that oil prices began to recede by 1980 because of the deregulation of the oil industry and increased production in oil producing countries like the Soviet Union could not turn around the impression that Carter's poor handling of the economy and of foreign affairs had contributed to a growing sense of impotence on the part of many Americans. The image broadcast across the nation of cars waiting in long lines for fuel was politically devastating for President Carter, as was the perception of weakness in the face of foreign manipulation of the U.S. economy.
The two events that can be considered the final straw for the Carter presidency and for the political transformation that resulted in Reagan's election were the Iranian hostage crisis and the Soviet invasion of Afghanistan. Those two events further cemented negative perceptions of Carter's presidency.
To summarize, economic difficulties and the energy crisis, the Iranian Revolution and subsequent hostage crisis, and the Soviet invasion of Afghanistan all contributed strongly to the rise of conservatisim and Ronald Reagan's election as president.