In the first Fox News Power Rankings House forecast, Republicans overall have more districts in their corner, but the race for a House majority remains as toss-up.

Wisconsin's U.S. Senate race will officially be set in Tuesday's primary, while the power of former President Donald Trump's endorsement will be tested in a Republican congressional primary as Democrats decide on a candidate in a swing House district to take on a GOP incumbent.

Republicans have a favorable Senate map this year, but with an open West Virginia race, and a series of strong incumbent Democrats, it is anyone's game.