Looking at the House of Representatives, let's start with California. There are 5 seats there--out of the 53--that are on several watch lists. Here are the details. One is an open seat, one is held by a Democrat and 3 by Republicans. Of the incumbents; 1 is a freshmen, 2 have been elected twice, and another 3 times. There is always an advantage to longevity in House offices--experience equals contacts and value added. So let's look at the particulars.
A) Seat 07 is crafted around the eastern side of Sacramento. It is held by 2 term incumbent Ami Bera. Representative Bera is unique in many ways. His background is that of a physician. He is the only ethnic Indian-American in congress. As a congress-critter he has amazing constituency services. The Republican opponent is Scott Jones. Mr. Jones is the twice-elected sheriff of Sacramento County. Mr. Jones stakes his credentials on his law & order service. He is an attractive candidate on purely conservative principals, but I don't see him in this present climate usurping an established politician, not that it won't be close.
B) Seat 10 is held by Jeff Denham who is a restrained conservative Republican with 3 terms of representing this district. It rates as just Republican by virtue of it recent history, however it is in a part of the state that is growing and become more Democratic. The critical constituency will be the Hispanic vote. His challenger is a beekeeper farmer named Michael Eggman. HE is a very charismatic and down to earth progressive who is providing Denham with a run for his money. Toss-up
C) Seat 21 is very similar to Seat 10 except that it's already tracking just Democratic. The 2 term representative is the rarest of all creatures, a moderate Republican. He has worked hard to help meet the needs of his constituents, however, like other moderate Republicans before him, he still falls into line on the big stuff. His challenger is a Emilio Huerta a small business owner and long time immigrant activist. He has strong name recognition and supplants Valadao's cache with the Hispanic community. Valadao is the son of Brazilian immigrants. This is another seat that will hinge on the Hispanic turnout. Toss up.
D) Seat 24 is open for the first time in a long time with the retirement of Democratic veteran Lois Capps. A marginally Democratic leaning district, in a different climate Republicans might have had a shot at it, but in this election I think that the Republican candidate Justin Fareed is just padding his resume against the Democratic candidate Salud Carbajal. For Fareed this run is his second bight at this apple have lost to Capps in 2014. Carbajal comes to the campaign from a decade of elected office on the Santa Barbara county board of supervisors, and has election has received priority backing from the DNCC. Further, in the primary Carbajal received over 66,000 votes to Fareed's 42,000. I think this seat is a keeper.
E) Seat 25 is currently held by freshman Republican representative Steve Knight. The seat sits in a bed of Democratic leaning districts, although it leans slightly Republican. Knight is a conservative Republican with a background in a law enforcement (18 years on the LAPD) many of whish were spent in a program that has been discredited as racist (CRASH: Community Resources Against Street Hoodlums). He is also a strong support of gun rights and the NRA and is outspoken against the Social Security program, calling it a "failed system" as recently as May 2016 during a public primary debate. There is no question that Knight is a card carrying conservative, the only question is where or not he's too conservative for his changing district. His opponent is Bryan Caforio. Caforio is taking Knight on head to head over the issue of Social Security. He also supports economic justice issues like equal pay for women, a living minimum wage and higher taxes on the super-rich. With a clear contrast between issues, the voters of the 25th district will have a clearcut decision to make in November. Toss-up.
All of these seats rest on the coattails of the Presidential election. The issues that are being presented by the campaigns of Clinton and Trump will drive voter turnout. This is not a good year to alienate, insult and attack women and minorities--and in California that means Hispanic voters. In all of this I can see 4 seats total for the Democrats.