this election is obviously going to be fascinating for a lot of reasons, but the biggest thing to me is going to be how the RNC approaches the entire election, not just the president.
normally, you support the presidential candidate, and his popularity or appeal trickles down, which helps those running for the senate, the house, and then the governors races statewide. in this case, the RNC hates trump, the support and enthusiasm has been tepid at best, and notable politicians up for re-election/running to get into government are distancing themselves from trump.
the RNC could basically go nuclear, punt the white house for 4 years, and make a huge push to keep the senate and keep their margin in the house. if they spread themselves thin or if their support for trump hurts the downballot candidates, it could be a huge disaster.
here is a quick summary:
senate - currently 54-44-2 (both independents caucus with the dems, so its really 54-46)
up for grabs seats: republicans 24, democrats 10
retiring: republicans 3 (IN, LA, FL), democrats 3 (CA, MD, NV)
only reid's seat in nevada is really considered a battleground race at this point. 5 of the republican senate seats are considered battleground races (FL, IL, NH, PA, WI)
democrats gained an average of 5 senate seats in the last 2 presidential election year cycles. republicans do better in mid-term elections.
house: 246-188-1
retiring: 20 republicans, 9 democrats
dems obviously have almost no chance to swing the house back, but they can put a dent in the republicans' majority. they'd need 30 seats to swing it. not impossible, but close to impossible. if the dems could win 15-18 seats, they'd be in a position to build some strength for the mid-term in 2018.
higher voter turnout has historically favored democrats. if trump continues to alienate women and minorities and it leads to a huge turnout, this could be an election for the books. there is even talk about clinton possibly winning utah, which has gone republican for something like 13 straight presidential elections.
wild