There are many predictions that the Republican Party may win either or both houses of Congress on November 2, the day of the midterm elections!
Historical reality is that whenever the party in power has lost one chamber of Congress, it also has lost the other house! Also, on the average since the beginning of the 20th century and the administration of Theodore Roosevelt, the party in power loses an average of 28 seats in the House of Representatives, and an average of 4 seats in the Senate!
Although some prognosticators seem to think that the Democrats will lose enough seats (10) to give up control of the Senate, it still seems a long shot to most! And since the Republicans would have to gain 39 seats to win the House of Representatives, that seems a tall order too, considering that if any seats are lost by the GOP in either house, that makes it all the more difficult for them to gain either chamber! To consider that the GOP will not lose any seats in either house of Congress, at a time when there is an anti incumbent attitude out there, seems an unlikely event!
It seems likely that the Democrats will lose close to the average of seats in both houses, but doubtful they will lose much more, if any, when the dust settles! But we shall see soon enough!