One factor was the decline of the post-war economic consensus in Western capitalist countries. For many years parties across the political spectrum had committed themselves to certain economic policies in order to avoid a rerun of the Great Depression. Such policies included high levels of public spending, the maintenance of full employment, and an increased role for government in the provision of social welfare.
By the late 1970s, however, the consensus began to break down as the prevailing Keynesian orthodoxy was seen not to be working. Both inflation and unemployment rose sharply, leading some on the political right to look for alternatives. A case for radical economic reform had been made for a number of years by conservative figures such as Barry Goldwater and Ronald Reagan. But their message went largely unheeded during the heyday of post-war liberalism. However, by the late 70s, and against the backdrop of a struggling economy, more and more Americans began throwing their support behind a conservative, free market agenda.
A second reason was the increased prominence in American public life of the religious right. What had previously been little more than a fringe movement began to exercise considerable influence within the Republican Party, shifting the balance of power away from the East Coast Rockefeller establishment towards evangelical Christians, mainly in the South and West of the country.
If the advocates of monetarism, free market economics, and Public Choice theory gave conservatism its intellectual heft, the religious right provided its social ideology. There was a widespread sense of social malaise in the United States in the late 70s, with a perception among many that liberal policies of successive administrations had led to increased crime, drug abuse, and family breakdown. Christian groups were at the forefront of campaigns to defend traditional, Bible-based teachings in relation to social issues. In particular, the religious right led an increasingly strident campaign to get Roe v Wade overturned, or at the very least, to restrict access to abortions at the statewide level.
A third reason for the rise of conservatism was a sense that the United States was somehow losing its way on the international stage. The Carter administration had been perceived as weak in relation to the ever-present threat of the Soviet Union. Conservatives decried what they saw as an overreaction to the failures of the Vietnam War, culminating in a less assertive, more diplomatic approach to foreign policy.
When the Soviets invaded Afghanistan in 1979, it seemed that this assessment had been largely vindicated. But worst than that for conservatives was the deposing of the Shah of Iran earlier that year and the subsequent taking of American hostages. To conservatives, these dangerous developments were the direct consequence of what they felt was a weak, vacillating foreign policy on the part of the Carter administration. As a result, the United States stood greatly diminished on the world stage, they believed, leading many to conclude that a more robust, more ideological approach was needed if the United States were to regain its position of international authority.