The platform of the Republican Party of the United States has historically been based on American conservatism, contrasting with the modern liberalism of the Democratic Party. The positions of the Republican Party have evolved over time.

Until recently, the party's fiscal conservatism included support for lower taxes, smaller government, free market capitalism, free trade, deregulation of corporations, and restrictions on labor unions. However, starting under the first presidency of Donald Trump and dramatically accelerating in the second presidency of Donald Trump, there has been a major realignment away from fiscal conservatism and the free market towards state capitalism and protectionism through the imposition of large-scale tariffs on the U.S. import of goods from countries around the world, including to raise tax revenue.

The party's social conservatism includes support for gun rights outlined in the Second Amendment, the death penalty, and other traditional values, often with a Christian foundation, including restrictions on abortion.Paul Gottfried, Conservatism in America: Making Sense of the American Right, p. 9, "Postwar conservatives set about creating their own synthesis of free-market capitalism, Judeo-Christian morality, and the global struggle against Communism." (2009); Gottfried, Theologies and moral concern (1995) p. 12 In foreign policy, Republicans usually favor increased military spending, strong national defense, and unilateral action. Other Republican positions include opposition to illegal immigration, drug legalization, and affirmative action, as well as support for school choice, and school prayer.

Economic issues Historically, the Republican Party since the 1920s has adhered to an ideology of fiscal conservatism. By the 2020s, Republicans have largely abandoned fiscal conservatism as an ideological cornerstone.

Traditional Republicans strongly believe that free markets and individual achievement are the primary factors behind economic prosperity. To this end, they historically advocated in favor of laissez-faire economics, limited government, free markets and free trade, tax cuts, reduced government spending, privatization, and the reduction of government run welfare programs in favor of private-sector nonprofits and encouraging personal responsibility. However, beginning with the first presidency of Donald Trump, some Republicans have switched their support of free trade to trade protectionism in the lead-up to the imposition of nearly global tariffs in 2025 during the second presidency of Donald Trump. By 2025, Trump and Republicans largely abandoned traditional Republican orthodoxy about protecting and promoting the free market, instead, in one case, favoring state capitalism by taking direct government equity stakes in a major US corporation, Intel, in a shift described as a seeming embrace of socialism, Marxism or Maoism.

According to Ross Douthat, the party always had strong bases in the local business community, as well as the national Big Business corporations that emerged in the Gilded Age after the Civil War. That has been changing in the 21st century, as much of Big Business has moved left.The Republican Party in the Trump era remained a mostly pro-business party in its policies but its constituencies and rhetoric have tilted more working class and populist, with many Romney Republicans drifting into the Democratic coalition....much of corporate America has swung culturally into liberalism’s camp. That process was well underway a decade ago, but it’s been accelerated by anti-Trump backlash, the more left-leaning commitments of big business’s younger customers and (especially) younger employees, and the relative ease with which the radical-sounding language of identity politics can be assimilated to corporate management techniques. As a consequence, today’s G.O.P. is most clearly now the party of local capitalism — the small-business gentry, the family firms.... Much of the party elite wish to continue doing business with big business as before. But the party’s base regards corporate institutions — especially in Silicon Valley, but extending to more traditional capitalist powers — as cultural enemies, with too much consolidated power and too much interest in pressuring, censoring, and propagandizing against socially conservative views and policy.

Taxes A leading economic theory advocated by modern Republicans is supply side economics. Some fiscal policies influenced by this theory were popularly known as Reaganomics, a term popularized during the Ronald Reagan administration. This theory holds that reduced income tax rates increase GDP growth and thereby generate the same or more revenue for the government from the smaller tax on the extra growth. This belief is reflected, in part, by the party's long-term advocacy of tax cuts. Many Republicans consider the income tax system to be inherently inefficient and oppose graduated tax rates, which they believe are unfairly targeted at those who create jobs and wealth. They also believe private spending is usually more efficient than government spending. Republicans generally oppose the estate tax.

Between the 19th century and the early-20th century, Republicans favored tariffs to protect and encourage American industry and industrial workers. In 1896, the GOP platform pledged to "renew and emphasize our allegiance to the policy of protection, as the bulwark of American industrial independence, and the foundation of development and prosperity. This true American policy taxes foreign products and encourages home industry. It puts the burden of revenue on foreign goods; it secures the American market for the American producer. It upholds the American standard of wages for the American workingman."

Welfare The Republican Party opposes government run welfare programs for the poor, believing that it encourages laziness and dependence on the government. They instead advocate personal responsibility and self-reliance to empower citizens to take responsibility for their own lives. Republicans introduced and strongly supported the welfare reform of 1996, which was signed into law by Democratic President Bill Clinton and limited eligibility for welfare for thousands of American households.

Education Most Republicans support school choice through charter schools and school vouchers for private schools; many have denounced the performance of the public school system and teachers unions. The party has insisted on a system of greater accountability for public schools, most prominently in recent years with the No Child Left Behind Act of 2001. The act received bipartisan support in Congress and was signed by President George W. Bush. Many Republicans, however, opposed the creation of the United States Department of Education when it was initially created in 1979.

Health care The party opposes a government-run single-payer health care system, claiming it constitutes socialized medicine. It favors a personal or employer-based system of insurance supplemented by Medicare for the elderly and Medicaid which covers approximately 40% of the poor. In 2003, Congress passed the Medicare Modernization Act with bipartisan support creating Medicare Part D covering prescription drugs. It was signed into law by President George W. Bush.

Republicans have a mixed record of supporting Social Security, Medicare, and Medicaid. Congressional Republicans and the Bush administration supported to reduce Medicaid's growth rate; however, congressional Republicans expanded Medicare, supporting a new drug plan for seniors starting in 2006. House Republicans overwhelmingly voted for a proposal known as The Path to Prosperity and for major changes to Medicare, Medicaid, and the Affordable Care Act. Many Republicans support increased health insurance portability, laws promoting coverage of pre-existing medical conditions, a cap on malpractice lawsuits, implementing a streamlined electronic medical records system, an emphasis on preventative care rather than emergency room care, and tax benefits aimed to make health insurance more affordable for the uninsured and to promote universal access. They generally oppose government funding for elective abortions.

By 2020, Republican officials have increasingly adopted anti-vaccine activism and policy.

Labor unions

Since the 1920s Republicans have generally been opposed to labor unions, which comprise a major component of the Democratic New Deal coalition. Although unions have lost membership in the private sector since the 1970s, they have gained among public sector unions (such as school teachers). Republicans at the state level generally support various right to work laws that weaken unions. At the national level, Republicans supported the Taft–Hartley Act of 1947, which gives workers the right not to participate in unions, as opposed to a closed shop, which prohibits workers from choosing not to join unions in workplaces. Most Republicans are opposed to increases in the minimum wage, believing that such increases hurt many businesses by forcing them to cut jobs and services, export jobs overseas, and raise the prices of goods to compensate for the decrease in profit. As Taylor Dark has emphasized in his analysis of the enduring alliance between labor unions and the Democrats, the unions' "most virulent opponents have moved into the Republican Party".

Republicans elected with Tea Party support in 2010, most notably Governor Scott Walker of Wisconsin, have launched major efforts against public sector unions due in part to state government pension obligations along with the allegation that the unions are too powerful. Walker was challenged by a coalition of unions and Democrats, but beat back a recall effort and was reelected in 2014.Jason Stein and Patrick Marley, More than They Bargained For: Scott Walker, Unions, and the Fight for Wisconsin (2013).

Environment

Historically, more progressive leaders in the Republican party supported environmental protection. For example, Republican President Theodore Roosevelt was a prominent conservationist whose policies eventually led to the creation of the modern National Park Service. Republican President Richard Nixon was responsible for establishing the Environmental Protection Agency in 1970.

In 2006, Arnold Schwarzenegger, then the Republican Governor of California, signed into law a set of carbon emission regulations that were the country's first cap on greenhouse gases, and included vehicle emissions standards higher than those of the Federal Government. These regulations were opposed by the Bush administration. President George W. Bush publicly opposed ratification of the Kyoto Protocol on the claim that they unfairly targeted Western industrialized nations such as the United States while favoring major polluters such as China and India.

In 2000, the Republican Party adopted as part of its platform support for the development of market-based solutions to environmental problems. According to the platform, "economic prosperity and environmental protection must advance together, environmental regulations should be based on science, the government's role should be to provide market-based incentives to develop the technologies to meet environmental standards, we should ensure that environmental policy meets the needs of localities, and environmental policy should focus on achieving results processes."