It is estimated by political experts that there are 78 “Swing” districts in the House of Representatives, which could go either way in November.
History tells us that with the exception of 1934, and 2002, the party NOT in the White House always gains seats, and often a large number of seats, and takes over the majority in Congress, as in 1946, 1954, 1994, 2006, and 2010.
Since the Democrats only need 23 seats to switch control of the lower house of Congress, it is hard to imagine that this will not occur.
There are plenty of seats that could change due to the Trump policies and programs, particularly in states such as New York, New Jersey, Pennsylvania, Virginia, Ohio, Florida, and California, with selected seats in other states many of them “Red” for Trump.
More likely than just 23 seats is the possibility of a massive switch of seats, possibly as many as 40 or more seats going to the Democrats.
If such happens, which polls seem to show likely to occur, we will have the ability of the House of Representatives to fully investigate many scandals and controversies that have been pushed aside by the Republican majority.
And impeachment of Donald Trump would be likely in 2019, just as Robert Mueller comes to conclusions on his investigation of Trump for Russian collusion, obstruction of justice, abuse of power, abuse of the Emoluments Clause, and so much else.
Conviction would be difficult, nearly impossible, of Trump on impeachment charges, but his erratic behavior could lead to pressure for him to resign, and since Mike Pence wants to be President, do not be so sure he would not turn against his boss at some point, as hard as that is to imagine right now in late July 2018.