A patchwork republic: Polarization and the laboratories of democracy

President Donald Trump’s challenge to the status quo is unlike anything we have seen in the modern presidency. In foreign affairs, he is “reshaping the world order,” as a series of Brookings essays explains. The domestic corollary is a shift in the domestic order—from his critiques of the federal government to his assertion of federal powers in areas that have not previously seen federal dominance. While the outcome is unclear, Trump’s presidency and the polarization fueling it are resulting in a resurgence of federalism. After decades of federal expansion across administrations, states are taking independent action, with Republican and Democratic states increasingly following divergent paths. If this trend continues, it is possible that even after Trump’s tenure, the country will remain fundamentally divided.

The 21st-century return of states’ rights differs from the 20th century, when the concept was often invoked to counter federal actions regarding racial equality. However, the roots remain similar: the presence of political cultures that vary significantly by state. Back then, in a less polarized context, the trend toward nationalization in civil rights, environmental policy, and social issues was more widely accepted, as the two major parties often aligned on other matters.

But in the 21st century, that is not the case. Polarization has led to deep and passionate disagreement between the major parties. In this new political environment, federalism can serve as a safety valve. The optimal balance between national and state solutions to complex issues often evolves. In today’s divided country, federalism may offer a way to manage conflict and provide a testing ground for effective policy.

The following examples illustrate these trends across diverse policy areas, including abortion, elections, vaccines, immigration, and regulation.

When the Supreme Court overruled Roe v. Wade in 2022, the ruling ended the federal constitutional right to abortion and shifted authority to the states. “Abortion presents a profound moral question,” the court wrote. “The Constitution does not prohibit the citizens of each State from regulating or prohibiting abortion. Roe and Casey arrogated that authority. The Court overrules those decisions and returns that authority to the people and their elected representatives.”

State legislatures immediately began writing new laws or amending laws that that predated Roe. In the four years since, states and territories have adopted a patchwork of abortion laws. Eleven states passed measures expanding abortion access, in some cases incorporating those protections into state constitutions. Some of these states also enacted legal protections for patients traveling from other states to seek the procedure and for the medical professionals who provided or otherwise assisted with those services.

Another 14 states and the District of Columbia moved to protect abortion access with some limitations, such as parental involvement for minors or bans after a certain point in pregnancy (gestational bans). Three states and two territories (Puerto Rico and the U.S. Virgin Islands) allow abortion but have no statute protecting it as a right. Another 10 states and two territories (Northern Mariana Islands and Guam) have passed laws that allow but severely restrict the procedure. For instance, a ban after six weeks of pregnancy is considered especially restrictive because many people do not know they are pregnant at that stage. Finally, 13 states outlaw abortion, in some cases including criminal penalties for providers.

Along the way, there have been attempts by some states to impose their views on residents who travel out of state for an abortion and on physicians in other states who provide information or medication. Generally, however, these attempts have failed, and the country has settled into a landscape of vastly different abortion laws from state to state.

The COVID-19 pandemic began in January 2020. As the country locked down, states realized that they needed to determine how to hold the November election during a pandemic where voters might avoid crowded polling places. This led to one of the most significant overhauls of elections in American history, as states moved to make voting by mail more accessible. Before the pandemic, only a few states—Colorado, Oregon, Washington, and Utah—mailed ballots to all registered voters. In preparation for the 2020 election, five more states and the District of Columbia moved to universal mail-in voting, most notably California. Other states implemented no-excuse absentee voting, making it easier than ever to request and submit a ballot.

Following the pandemic, mail-in voting remained a prominent feature of the American electoral system. Today, eight states and the District of Columbia conduct all elections by mail, while another 15 states allow the practice in specific counties or under certain conditions. With the exception of Utah, the states that have implemented universal mail-in voting generally trend toward the Democratic Party.

Before the 2020 election, mail-in voting was not a particularly partisan issue. But in the run-up to the 2020 election, President Trump argued that mail-in ballots were vulnerable to fraud and spoke out against their use. Consequently, a significant divide emerged between the parties that year: Democrats largely utilized mail-in voting, while Republicans generally did not.

Looking ahead, 28 states offer “no excuse” absentee balloting, making it relatively accessible for voters to cast their ballots. These states are divided nearly evenly among Republican, Democratic, and swing states. However, of the 14 states and two territories—Puerto Rico and the U.S. Virgin Islands—that require an excuse to vote absentee, the vast majority lean Republican.

In the run-up to the 2026 elections, Trump continues to criticize states that allow mail-in voting, but he has also focused on the issue of noncitizen voting, leading to his support for the Safeguard American Voter Eligibility (SAVE) Act. While it has been illegal for noncitizens to vote in federal elections since 1924—with a 1996 law imposing further criminal penalties—most states currently enforce this by having voters attest to their citizenship under penalty of perjury and checking rolls against government databases.

The SAVE Act would instead require individuals to provide “documentary” proof of citizenship, such as a passport or birth certificate, at the time of registration. Because many eligible voters lack immediate access to these specific documents, some Democrats and voting rights advocates argue that a strict implementation would disenfranchise a significant number of Americans. Although the House passed the legislation in February 2026, its path through the Senate remains uncertain.

Federal law does not apply to state contests, so between 2009 and 2025, nine states and Guam passed laws requiring proof of citizenship to vote. Three other states—Arkansas, Kansas, and South Dakota—have referred similar constitutional amendments to the November 2026 ballot. While the majority of these are Republican-led states, the issue has also emerged in swing states like New Hampshire and Arizona, which have maintained conservative-leaning legislatures.

When President Trump appointed Robert F. Kennedy Jr. as secretary of health and human services, he installed the first head of the department to have publicly questioned the safety and efficacy of vaccines. Despite assurances provided to lawmakers such as Sen. Bill Cassidy (R-La.) during his confirmation hearings, Kennedy proceeded to radically change the department’s long-standing vaccine recommendations. By June 2025, he had replaced all 17 members of the Advisory Committee on Immunization Practices (ACIP) with new appointees who had “expressed skeptical views on vaccinations.” For decades, states have relied on this committee’s guidance to determine school immunization requirements and insurance coverage mandates.

Since then, a series of controversial decisions regarding COVID-19 vaccines, and specifically the vaccine schedule for children and infants, prompted serious backlash from medical organizations. The American Academy of Pediatrics (AAP) characterized the move “dangerous and unnecessary.” In response, states began taking matters into their own hands. Following Kennedy’s lead, Florida removed its vaccine requirements for children in public schools.

Significant developments also occurred in Democratic-led states. Massachusetts, a powerhouse of medical care and research, was among the first to act by introducing legislation to remove references to ACIP from its statutes. The state instead proposed a regional committee to coordinate vaccine recommendations among New England states. Meanwhile, Washington, Oregon, and California banded together to create their own vaccine advisory system. As of early 2026, 17 states have either removed statutory references to the federal committee in favor of AAP guidelines or incorporated the AAP into their state policies for establishing vaccine requirements.

The modern “sanctuary” movement, as it applies to immigration, began in 1979 in Los Angeles. While there is no single legal definition of a sanctuary city or state, the term generally refers to jurisdictions that pass laws preventing local personnel, particularly law enforcement, from cooperating with federal authorities seeking to deport undocumented immigrants. The number of such jurisdictions remained small through the late 20th century but increased significantly between 2016 and 2025 as the Trump administrations focused on immigration enforcement. Today, it is estimated that there are more than 1,000 sanctuary jurisdictions across the country.

President Trump focus on mass deportations has intensified the debate over sanctuary jurisdictions, spurring legislation designed to counter the movement. Tom Homan, Trump’s border czar, has threatened many sanctuary cities with a variety of penalties if they don’t cooperate with Immigration and Customs Enforcement. At the same time, Republican-led states such as Texas and Florida have mandated that local law enforcement cooperate with federal immigration enforcement measures.

In 2026 alone, 56 bills have been introduced in state legislatures concerning how states and localities interact with immigration authorities. In Iowa, Kentucky, and South Carolina, proposed legislation would require state law enforcement to cooperate with immigration actions. In Mississippi and West Virginia, the proposed laws would impose sanctions on sanctuary jurisdictions. As the Immigrant Legal Resource Center’s “State Map on Immigration Enforcement” illustrates, the states pursuing these stricter measures are consistently Republican-led.

With the Trump administration’s decision to end its enforcement surge in Minneapolis, the issue of local cooperation with federal immigration authorities may retreat from the front pages, at least temporarily. However, the operation leaves in its wake a patchwork of local, state, and federal regulations that closely correlate with the partisan control of those jurisdictions.

Two REINS acts are pending in the 119th Congress. REINS—which stands for “Regulations from the Executive in Need of Scrutiny”—is a legislative concept that emerged from the Tea Party movement. It seeks to grant Congress greater oversight of executive branch rulemaking by “requiring preemptive approval by Congress for major rules” before they can take effect. The movement to restrict executive rulemaking has expanded to the state level as well. Nine states have passed REINS-type laws seeking greater legislative control over executive branch rulemaking. All but one of these states—Wisconsin—were heavily Republican states.

Those who support REINS-type legislation do so because they believe the executive branch continually oversteps its power through the regulatory process. But those who oppose it believe it would politicize the regulatory process and supplant the scientific and technical background that currently goes into rulemaking. At risk would be environmental regulations, food safety regulations, health regulations, and a host of others.

The Trump Administration has three more years to remake the federal government. A new Congress could slow this down, but they may not need to. We are already turning into two nations along partisan lines.

In one set of states, abortions are so severely restricted as to be almost impossible to obtain. In a similar set of states, voters face bureaucratic hurdles, and vaccine guidance is no longer provided at the state level. Furthermore, many of these same jurisdictions have mandated that law enforcement cooperate with immigration crackdowns. And in many of them, legislatures can now override regulations by vote, often without regard to scientific or technical justifications.

Article 10 of the Constitution states: “The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.” It leaves many areas of public policy up to the states. This provision leaves many areas of public policy to the states. The movement toward same-sex marriage began in states and localities before it became federal policy, as did the transition toward welfare-to-work programs before President Clinton signed major welfare reform legislation.

This rebirth of federalism, anathema to some and long overdue to others, will eventually result in many experiments. In a 1932 dissenting opinion, Justice Louis D. Brandeis wrote, “It is one of the happy incidents of the federal system, that a single courageous State may, if its citizens choose, serve as a laboratory; and try novel social and economic experiments without risk to the rest of the country.” State action has created a perfect “laboratory of democracy”—a term coined by Brandeis and used by author David Osborne as the title of a book—to describe the ability of states to pursue different policies and evaluate their outcomes. As Republican-led states align with the Trump administration and Democratic-led states chart their own course, the results will show which policies make a difference.

Take, for instance, states establishing their own vaccine policies. KFF (formerly the Kaiser Family Foundation) summarized the situation as follows:

“The recent moves by many states to decouple their vaccine policy determinations from federal recommendations to ensure continued access, as the federal government takes steps that narrow access is unprecedented and will likely continue as the federal government pursues further changes to vaccine recommendations. This divergence between federal policy and the states and among states ultimately means that vaccine coverage and access could increasingly vary according to where one lives.”

In a relatively short period of time, the results of this particular “laboratory of democracy” should become clear. Some states may experience significant death tolls among children from diseases like measles or polio, while others may not, depending on the vaccine strategy chosen.

As more states move away from federal guidance to establish their own policies, these laboratories will be studied. Will states with restrictive abortion laws have higher incidences of maternal death? Will states that restrict forms of voting have lower turnout rates? Will states where local law enforcement cooperates with federal immigration officials be more effective and make fewer mistakes than states where they do not? Finally, will states allow legislatures to dictate rulemaking in the face of environmental, health, or even financial crises?

If these trends continue, the laboratories of democracy will teach us much—but, perhaps, at a cost.