Analysts said that issues addressed by state legislatures this year, which included gun control, health care, education and police procedures, might have more immediate, lasting effect than anything approved in Washington, D.C., where government is divided.

The roots of the polarization in state legislatures can be traced to elections in 2010, when Republicans made decisive gains in statehouses and pressed for policies that included restricting labor unions and abortion access, while expanding gun rights, according to Sarah F. Anzia, a political scientist at the University of California, Berkeley.

Around the same time, Dr. Anzia said, national organizations representing interest groups ranging from teachers to gun owners became more active in state capitals, because they found it far easier to make headway in places like Sacramento and Charleston, W.Va., than in Washington because of gridlock in Congress.

The number of states with either supermajorities of Democrats that also have Democratic governors (California, Nevada and Oregon, among others) or Republicans with Republican governors (Alabama, Ohio and Tennessee, among others) has grown, too, meaning that many lawmakers rarely feel the need to compromise.

“If you are a Republican in one state, you are probably going to be pushing the same agenda as a Republican in another state, and the same is true for Democrats,” said Dr. Anzia. “That hasn’t always been true, and the result is that now more than ever, state legislatures are key players in these partisan battles over politics.”

In Minnesota, the only state left with a divided legislature, promises of bipartisanship sometimes devolved into stalemate.

During a budget standoff last month, Tim Walz, the Democratic governor who campaigned last year on a pledge to work across the aisle, angrily denounced Republicans for blocking gun control efforts and supporting deep tax cuts, saying those policies “fit better in Mississippi and Alabama than they do in Minnesota.”