As national Republicans dig in to defend their majorities in Congress in the midterm elections, party leaders across the country have grown anxious about losses on a different front: state legislatures. Over the last decade, Republicans have dominated most state capitals, enacting deep tax cuts, imposing new regulations on labor unions and abortion providers, and drawing favorable congressional maps to reinforce their power in Washington.
Yet that dominance appears to be fraying, strained by the same forces taxing Republicans in Congress. National strategists in both parties see the landscape of legislative races expanding, especially in areas around major cities where President Trump has stirred an insurrection among liberals, and college-educated voters and white women have recoiled from Republicans.
Over the last year, Democrats have snatched away Republican seats in more than a dozen special legislative elections from Seattle and Tulsa, Okla., to Atlanta and Miami, in many cases electing female and minority candidates with strong turnout on the left.
Republicans will not be easily dislodged: In many states, Republican governors have built powerful machinery to defend their allies, and Mr. Trump remains popular enough across much of the Midwest and South to limit Democratic gains. In 31 out of 50 states, Republicans command the entire legislature; in 25 of those states, the governor is also a Republican.