Wonder what Washington might look like if it were less polarized? Just look to Rhode Island. The political scientists Boris Shor and Nolan McCarty analyzed state legislative voting records from 1996 to 2013 and found Rhode Island had the least ideological difference between the typical Republican and Democratic lawmakers.

It’s common for Republican officials in heavily Democratic Northeastern states to be moderates. What makes Rhode Island stand out is the number of conservatives within its Democratic legislative supermajority. The median Democrat in Rhode Island was more conservative than in all but 13 state legislatures, scoring directly between Georgia and Indiana and far to the right of those in Connecticut or Massachusetts.

“Lots of Democrats here would be Republicans somewhere else, but they don’t feel they can win without a ‘D’ next to their name,” says Representative Brian Newberry, the minority leader of the six Republican members of the state’s 75-seat House of Representatives. Observers on the left agree. “In Rhode Island, the Democratic Party not only has a big tent, it has a circus tent,” says Robert Walsh, who leads the Rhode Island affiliate of the National Education Association.

The Democratic speaker of the State House of Representatives, Representative Nick Mattiello, is seen as closer to the interests of business than to those of labor. “Basically, he’s a Republican,” says Wendy Schiller, a professor of political science at Brown University. In 2010, Lincoln Chafee, a former Republican senator, ran for governor as an independent; because Democrats picked a fairly conservative nominee, Mr. Chafee was able to run to the left of both major party candidates and win.