Period 9 runs from 1980 to the present. It examines continuing debates over government, economic and demographic change, and the United States' role in the world.

The conservative movement 保守主义运动 that organised in the 1960s and 1970s came to power with Ronald Reagan 里根. Its programme had three strands:

• Tax cuts and deregulation 减税与放松管制, on the argument that reducing the burden on business would raise growth - often called supply-side economics 供给学派经济学.
• Efforts to reduce domestic government programmes met resistance; defence spending 国防开支 increased as part of the military buildup.
• Appeals to social conservatism 社会保守主义, on religion, family, and law and order.

Tax cuts and deregulation changed policy, while opposition and the popularity of many programmes limited attempts to shrink government. Debates over free trade, the social safety net and financial regulation continued.

Try it — identify the goal. Teacher-written cases grounded in CED Topics 9.2 and 9.3: tax cuts and deregulation aimed to encourage private economic activity; the military buildup opposed communism; social conservatives promoted traditional values. Match these to economic, foreign-policy and social goals. Does the military case fit “less government in every field”?

Worked comparison. The coalition combined different goals. Supply-side reasoning stressed incentives for work, saving and investment; military policy used federal resources; social conservatism involved values beyond the economic argument. Reduced regulation did not mean federal power disappeared.

Source practice — Reagan's September 1981 economic-recovery address, paraphrased. Reagan expected tax cuts to stimulate growth and jobs, spending restraint to reduce deficits, and less regulation to ease business burdens. Identify a policy and its intended effect. What further evidence would establish whether the aim was achieved?

Worked reading. A speech establishes the administration's argument, not independent proof of success. Compare implementation, economic performance and budgets. The CED records tax cuts and deregulation alongside resistance to shrinking popular programmes. Do not treat expected growth as a universal rule that tax cuts pay for themselves.

Three developments help describe the economy after 1980:

• Globalization 全球化 - cross-border trade, production and economic connections.
• Deindustrialization 去工业化 - declining manufacturing employment, alongside growth in service work.
• Technological change 技术变革 - computing and then the internet, which transformed productivity, work, and communication.

Digital communication increased productivity and worldwide economic opportunities. These gains coexisted with stagnant working- and middle-class real wages and growing income inequality 收入不平等.

Try it — identify developments and overlap. Teacher-written cases grounded in CED Topic 9.4: A, digital communication helps a business reach customers abroad; B, manufacturing employment falls while service employment rises; C, computing and the internet change work and access to information. Match the cases to globalization, deindustrialization and technological change. Can one case involve more than one development?

Worked classification. A involves global connections and technology. B describes a sectoral employment shift; it does not establish that every job moved abroad or that manufacturing vanished. C concerns technology's wider effects. Identify the pattern before explaining its cause.

Try it — assess distribution. The CED describes increased productivity alongside stagnant working- and middle-class real wages and rising inequality. Does higher productivity prove all workers gained equally?

Worked judgment. Productive capacity and income distribution are different. Growth can coexist with unequal gains. Employment shifts and declining union membership describe the setting, but listing trends does not measure their causal weights. An explanation needs evidence about the group, dates and mechanism.

Migration and immigration 人口迁移与移民 in the 1990s and 2000s continued to reshape the population, with growth in arrivals from Latin America and Asia 拉丁美洲与亚洲 following the 1965 reform of immigration law.

The consequences are the examinable part: population growth in the South and West, the growth of multi-ethnic cities, ongoing debate over immigration policy 移民政策 and border enforcement, and continuing arguments about citizenship 公民身份 and national identity - the same argument the course has traced since Reconstruction.

The period's later topics group around a small number of developments:

• The September 11 attacks 九一一袭击 and the response - military intervention abroad, a new security apparatus, and renewed debate over the balance between security and civil liberties 安全与公民自由.
• Economic crisis in 2008 and the argument over government's role in stabilising the economy.
• Political polarisation 政治极化, amplified by changes in media and communication.
• Debate over climate and energy 气候与能源 policy.