State legislatures, always the undercard of the nation’s elections, are suddenly important.

The U.S. Supreme Court’s ruling last month that gave states broader powers to draw the political maps defining control of Congress have added a new dimension to legislative races.

Right now, it seems that’s better news for Democrats than Republicans.

“Grassroots takes on a whole new meaning when indeed you set the control of Congress,” said Colorado Senate President Joan Fitz-Gerald, a Democrat. “Potentially, in some states, a shift of power means a shift of congressional seats.”

In a decision upholding Texas’ contentious 2003 redistricting, the Supreme Court ruled that states could conduct redistricting whenever they wished, rather than the traditional once-a-decade schedule following release of new census figures. Texas’ new congressional map helped the GOP win six House seats.

Such shifts will probably remain rare even with the high court ruling, since one party needs to control both the legislature and governorship, and the process is exhausting and tends to dominate a legislative session. Not all state constitutions would allow it. But it does open the door, and it means state races can have a much greater national impact.

Statehouse control has seesawed for the past decade. Solidly Democratic for a quarter-century, legislatures were put into contention by the 1994 Republican landslide.

Now Republicans are up slightly – with 20 legislatures entirely in GOP hands, 19 in Democratic control and 10 split (Nebraska is nonpartisan). Of the nation’s 7,382 legislative seats, Democrats have a slight edge – by 21 seats.

The narrow divide is reflected within the individual legislatures. In more than 20 states, one or both chambers could see power change hands with a shift of just five or fewer seats.

This fall – with a major midterm battle for Congress, 36 races for governor and polls showing a dissatisfied electorate – many strategists and observers think there’s a chance for a shift among state legislatures that could give Democrats more seats and more statehouses.