With the inauguration of President Biden and Vice President Harris, the Democratic Party has unified control of the federal government — the presidency and both houses of Congress — for the first time since 2010.

Democrats have razor-thin majorities in both chambers. The Senate is split 50-50, allowing Harris to cast the tie-breaking vote; the House is divided 221 to 211.

Nevertheless, Democrats like Senate Majority Leader Charles E. Schumer (D-N.Y.) have promised to pursue “bold change,” including tackling climate change, voting rights and statehood for the District of Columbia. At the federal level, Republicans will be unable to block Democrats or meaningfully advance their own policy priorities.

We can expect Republicans to push back in states that they control, our research finds.

Red states get redder, and blue states get bluer when the opposing party is in power in Washington

In a forthcoming article in the British Journal of Political Science, we examined whether the national balance of power influences policymaking in states where one party controls the government. Using political scientists Devin Caughey and Chris Warshaw’s measure of policy ideology, which examines each state’s policies on a liberal to conservative scale, we analyzed how each state’s annual change in policy liberalism related to which party held power in Washington. We found that from 1974 to 2019, states controlled by one or the other party pushed policy furthest in their preferred ideological direction when the opposing party controlled the federal government.

This is a comparatively new phenomenon, happening more often since the mid-1990s, when U.S. politics began to be more polarized, with a large and growing gap between Republicans’ and Democrats’ beliefs. In an era when the parties are especially at odds and fighting over every policy decision, many partisans find having the opposing party control the federal government to be especially threatening. As Sen. Ted Cruz (R-Tex.) put it, a Democratic victory in the Georgia runoffs would mean “no check whatsoever on the most radical policies of the Democratic left.” As a result, he implied, not only will Republican Party policy ideas be ignored federally, but existing achievements also might be scaled back or eliminated altogether.

That threat fuels state policy activism in those states where the out-party does hold power.

What does that mean in practice? States controlled by the opposition aggressively resist federal policy initiatives while strengthening state laws related to existing policy priorities. For instance, under the Trump administration, California passed bills to enact “net neutrality” rules, more strictly regulate gun ownership and set aggressive new environmental goals. At other times, a state might act on policy areas like immigration that have typically been left to the federal government, as when Arizona enacted immigration laws in 2010 that allowed state law enforcement officers to arrest and detain suspected undocumented immigrants.

What might red states do now?

First, Republican-controlled states are likely to resist any Biden administration actions that require state cooperation. That’s what happened when the Obama administration enacted its initiatives. In response to the Affordable Care Act, Republican state governors rejected federal funding for the expansion of Medicaid. In response to Obama’s Clean Power Plan, many states sued the Environmental Protection Agency, claiming it lacked the authority to regulate carbon emissions at the state level. Republican state attorneys general are also likely to take any Biden initiatives to court, arguing they are unconstitutional, as happened repeatedly under the Obama administration, and as Democratic attorneys general did repeatedly in response to Trump’s initiatives.

Second, Republican-controlled states are likely to take action on policy areas in which the Biden administration and Democratic Congress are likely to roll back Trump’s initiatives. For instance, Biden reversed Trump administration policies on immigration and environmental regulation on his first day; Republican-controlled states may well legislate or take executive action in these areas. Already, Texas Gov. Greg Abbott (R) has claimed the state will “redouble” its border security efforts under a Biden administration.

Finally, given Trump’s unsubstantiated allegations of voter fraud, Republican-controlled states may enact laws limiting the right to vote. For instance, Republican lawmakers in Georgia have already signaled they’ll restrict mail-in voting. In Wisconsin, Republicans have drafted a bill to reallocate the state’s 10 electoral votes by congressional district; had this been in place in November, Trump would have taken roughly half of the state’s electors, even though he lost the state’s popular vote by about 20,000 votes.

Since about the 1980s, the U.S. federal government has usually been divided between Republicans and Democrats, punctuated by brief periods in which one party controlled Congress and the presidency. For example, over the nearly four decades from 1981 to 2020, there have been only 10 years in which one party controlled all three centers of federal power, with the White House and both chambers of Congress. But increasingly in the states, one party controls power. For instance, while only 22 states were controlled by a single party in 2001; by 2020, that number was 38.

As a result, unlike in Washington, state partisan majorities are increasingly free to run their governments as they believe best and to air or pursue partisan grievances about national politics. In the current polarized environment, the policy decisions of the federal government hit close to home, and any swing in Washington ends up affecting how states legislate and govern.

Nicholas Miras (@nicholasmiras) is a doctoral candidate in government and politics at the University of Maryland. He studies American politics and political methodology, with an emphasis on state policymaking and federal-state relations.

Stella M. Rouse (@Stella_Rouse) is associate professor and director of the Center for Democracy and Civic Engagement at the University of Maryland, co-author most recently of The Politics of Millennials: Political Beliefs and Policy Preferences of America’s Most Diverse Generation (University of Michigan Press, 2018), and serves on the executive board of the Women Also Know Stuff initiative.