The U.S. midterm elections of Nov. 6 are attracting worldwide attention because they will constitute the first "national referendum" on the presidency of Donald Trump.
Four results are possible: (1) both the House of Representatives and the Senate remain with the Republican Party in the majority; (2) the House turns majority Democratic but the Senate remains majority Republican; (3) the Senate turns majority Democratic but the House remains majority Republican, and (4) both the House and the Senate turn majority Democratic. With less than a month to go, it appears that (2) has the highest probability and that (3) has the lowest probability.
In the House — where all 435 seats are up for election — Democrats need to flip 23 seats to gain the majority. This appears possible, although gerrymandering, voter suppression and unlimited campaign financing made possible by the Supreme Court's 2010 Citizens United decision all favor Republican candidates.