Shifts among undecided voters or unexpected changes in turnout in these races could decide control of the House-and in one possible outcome, a Democratic majority won't become clear until late postal ballots are counted in California and Washington. That narrative is based largely on national polls, and caution should be urged.
How it would happen: The idea that we might continue to fundamentally misunderstand the country's political zeitgeist - combined with the 2016 election - mean there could be something completely unexpected.
If moderates are aghast at Trump's constant appeal to the fringe, his loyalists believe that Trump's success speaks to the more mundane, structural causes of inequity and racial polarisation. Numerous races are rated toss-ups, and close results may be subjected to run-offs or recounts. Twenty-six of the 35 Senate seats at stake are held by Democrats and nine are held by Republicans.
For two years, Republicans have been without a compass. That right there is and has been a huge flashing red light for the GOP. They could possibly even obtain those tax returns that Trump clearly does not want us to see and expose what the New York Times has said are fraudulent tax schemes.
Current polling shows the Republican-led U.S. House of Representatives could flip to Democratic control with 39 toss-up elections deciding who controls that legislative body in 2019. Among registered voters, 71 percent say the economy is good or excellent, up from 60 percent in August. And where do a lot of those women live?
In 2010, the Tea Party swing of 63 seats gave the Republicans the House: Barack Obama would never get control of it back. Without it, Trump's hand would be considerably weaker. Conservative Party candidate Sam McCann, a Republican state senator, will take from 5 to 7 percent of normally GOP votes away from Rauner.
In the U.S. Senate, 32 seats are up for grabs this November, but 23 of them are now held by Democrats.
BUY MACHINERY STOCKS Analysts at Stifel see Trump quickly proposing a "Highway Bill" when the House takes office if Democrats win control of the lower chamber That may lead to increased political rancor and Trump may take the high road of "the people's business" by proposing a transportation bill, benefiting Caterpillar and Deere & Co. They promised hardline immigration policies and more tax cuts, arguing that Democrats would erase two years of progress. If they can hold Republicans to net even, keeping the Senate at 51-49, or maybe lose a net of one seat, then they will be very happy. "And there's no way they'll be able to spin it as anything other than that".
This would be a huge win for the GOP. Turnout in the last two midterm elections was between 40 percent and 50 percent of registered voters.
Democrats are pushing healthcare with poll after poll saying it's the number one issue - along with the economy - for many voters. And who pays for polls for the most part?
Given Trump's stunning victory in 2016, few were confident in their predictions. More foreign workers are reporting outright visa rejections.
It would also be yet another reckoning for pollsters and media organizations that pay for the surveys.
This is not seen as the likeliest of scenarios, but it's not out of the realm of possibility either. This agenda is on the line as well, since Republicans align with Trump on the issue. "The Democrats will do quite well in the House of Representatives, in the governorships and state legislatures".
"We're not some fringe element of the Democratic Party". "It's not for him", Trump said. It would have to trigger a degree of soul-searching - in at least some Republican corners.
Between Trump's "trade war", his renegotiation of worldwide treaties, robust USA growth and full employment, the economy is at the heart of this election.
Deadlines to register and get an absentee ballot are past, as is the deadline for civilians to submit an absentee ballot. In 2016, to the surprise of many, 319,000 absentee ballots were rejected for one reason or another.
Tuesday's results will be colored by the dramatically different landscapes in the fight for the House and Senate. Specifically, it could all come down to Mississippi.
Three states could elect their first African-American governors, while several others are running LGBT candidates and Muslims.