Certain things seem clear, and other things are unsettled.  Republicans seem to have momentum, both in House and in Senate races.  If you don't believe me, look at Nate Silver's models and forecasts at fivethirtyeight.com.  Nate Silver's model predicts the chances of a GOP takeover of the House are 81%.  Two weeks ago, the GOP chances for control were 68% according to him.

Most forecasts (RCP, Larry Sabato, Cook Political Report, 538) project final House numbers for the GOP in a range of 230 to 240.  Redistricting, which was played to the hilt in many states by both parties to the extent they could, has limited the number of competitive races.  Ohio and Illinois are probably the two states with the most partisan redistricting.

House races may produce some strange results this year.  The Democrats could win and hold Alaska's only House seat.  A Republican could win a House seat in Rhode Island.

For the Senate, Silver has GOP chances at 45%, 29% two weeks ago.  In other words, the GOP looks likely to win the House, and Senate control is very much a tossup.  Silver's model incorporates, among other factors, polling results (higher weights to more recent polls, and those with greater historic accuracy) and state or district voting history. 

At the moment, many Senate races are in play.  Democrat-held seats that could shift include Arizona, Georgia, Nevada, and New Hampshire.  Washington State and Colorado are uphill for Republicans, but very good candidates have made these races competitive.  GOP-held seats in play include Ohio, Wisconsin, North Carolina, Pennsylvania, and maybe Utah and Iowa.

One big difference between the parties is that vulnerable Democrats are all incumbents.  Three of the four most vulnerable Republican-held seats are open: Ohio, Pennsylvania, and North Carolina.  In most cycles, incumbency is a big advantage, especially in fundraising.  Challengers are sometimes not picked until the late summer and are underfunded for the general election. 

On the other hand, one factor working for Republicans in some of the closest Senate races are likely big wins for GOP governors: Ohio, Georgia, and New Hampshire in particular, as well as Iowa, and a stronger than expected GOP candidate for governor in Arizona.  In Pennsylvania, the Democratic governor candidate seems well ahead and is helping John Fetterman try to reach the finish line. 

Incumbency may be a mixed blessing this year.  Voters seem by and large miserable and unhappy (look at right direction, wrong direction surveys).  Inflation and interest rates are high.  Home values and stock market values have sharply dropped.  We have a national crime wave, focused on cities where Democrats are in complete control, and politicians seem unable or unwilling to address the problem.  Personal insecurity is a big deal.

New York State has a close governor's race, largely as a result of crime numbers.  Bail reform, stifling how police can behave, greatly reduced police staffing, and prosecutors more concerned with keeping criminals out of jail than protecting their victims are all making voters sour on this issue.

COVID lockdowns were often unnecessary and caused great economic damage and very poor educational results with kids schooled via Zoom.  The incredible number of illegals allowed in the country at our wide open southern border suggests national lawlessness, and almost a complete abdication of responsibility by the federal government. 

The Dobbs decision angered many women, and during the summer gave momentum to Democrats.  However, they have overplayed their hand.  Two thirds of Americans want to keep abortion legal.  But two thirds also favor restrictions, with few abortions after the first trimester.  

And of course there is the elephant in the room: a brain-dead president who is obviously not up to the job.  He was likely not up to it in 2020, but was cynically hidden from view by his handlers in order to get him elected.  Biden's basement campaign allowed the media to make Trump the issue in 2020.

Senate

Georgia: In 2020, the state had a near tie for the presidency, and two 1- to 2-point races for two Senate races on Election Day, and in runoffs two months later.  This year's Senate race has been close all the way.  Georgia is an evenly divided state.  The black share of the population and all voters rises every year.  However, Stacey Abrams has worn out her welcome and will likely lose decisively this year.  No, she did not win in 2018, and yes, she is an election denier.

Herschel Walker is a unique candidate with both strengths and weaknesses.  His Georgia football team won the national title, the last Georgia team to do so this until last year.  The Dawgs are ranked #1 this year.  Dawgs fans are happy, and this helps Herschel.  Governor Kemp is popular, and he helps Walker.

Of course, Walker's life story since his pro football days has been "uneven," and this has hurt him.  His opponent, Reverend Warnock, has not distinguished himself in the Senate and has to defend Biden and his votes in the Senate.  This is a tossup race, which means that with a libertarian drawing 3%, it is probably headed for a runoff.  Warnock's chances improve in a runoff with Governor Kemp not on the ballot and a strong Democratic ground game.  I think this race slightly leans toward the Democrats.

Arizona: Republican Kari Lake has been a surprisingly strong candidate for governor and seems likely to win.  This helps Senate candidate Blake Masters, who trailed badly but has closed the gap to a few points with a strong debate performance.  Senator Mark Kelly has coasted and run a tepid campaign.  A month back, the idea that Masters could win seemed fanciful.  Now it is a real possibility, and he has the momentum.

Nevada: The GOP recruited the candidate it wanted in Nevada, and Adam Laxalt has been tied or narrowly ahead of Catherine Cortez Masto for a few months.  Nevada is a state that breaks Republican hearts: one narrow defeat after another (like Florida and North Carolina for Democrats).  This year looks like a breakthrough, though it is very close.

Wisconsin: Ron Johnson seems in good shape here because his opponent is so bad.  Mandela Barnes is an anti-police, race-obsessed crazy with a history of provocative statements, which are all coming out.  Johnson has been ahead in every recent poll, and the state has a history of under-polling Republicans.  A poll two weeks before Election Day in 2020 had Biden up 16 on Trump.  He won by 0.6%.

New Hampshire: Democrat Maggie Hassan is another Democrat who seemed to be coasting to victory.  Now two new polls have her up 1 and 3 against Don Bolduc, a career army general who is underfunded and seemed too conservative for the state.  Governor Chris Sununu would probably have won this Senate seat easily had he run, but governor is a much better job than senator, especially if you are in the minority.  I think Hassan will win, but she may sweat a bit before Election Day.

Ohio: Rob Portman retired.  He won this seat by 20%.  Ohio has moved toward Republicans, and J.D. Vance seems to be a few points ahead of Congressman Tim Ryan.  But Governor DeWine is up by over 15 points, so Vance is badly underperforming.  Ryan is trying to imitate the campaign of Senator Sherrod Brown, a Democrat with appeal to the white working class.  He is a good candidate for this state.  Republicans are nervous about this race, though I think Vance is slightly favored.

North Carolina: Both parties have nominated solid candidates for this open seat, Ted Budd for 
Republicans, Cheri Beasley for Democrats.  Budd has maintained a small 2- to 3-point lead for a few months, consistent with statewide contests in recent years.  Democrats have not focused on the race as they have in other states, which might suggest they are not confident that a major effort will succeed.

Pennsylvania: A month ago, Mehmet Oz's chances of winning seemed to match John Fetterman's chances of completing a sentence.  Now the race is close to even, though Oz has never led a single poll.  Pennsylvania is a conservative state, sometimes described as Philadelphia and Pittsburgh with Alabama in the middle.  The state is near the top among states with highest percentage of current residents born in the state.  Think about it: do you know a lot of people who want to move to Philadelphia?  Of course, the same question can be asked about Chicago at this point.

Oz has campaigned doggedly.  He is hampered, I think, by the fact that he lived for a much longer time in New Jersey than Pennsylvania.  He is also a Muslim with dual citizenship in Turkey.  None of this helps him in the campaign.  He might win since Fetterman is so obviously a terrible candidate and at this point seems unable to serve.  Fetterman has been on the wrong side of the crime debate, calling for a release of a third of those in prison including violent offenders.  Philadelphia has a murder rate that rivals that of Chicago.

Then there is his daily dress code, which is an affront to civilization.  Is this the best Democrats could come up with?  I think this race could go either way, though the one debate yesterday was a disaster for Fetterman.

I think Senate control comes down to Georgia, Pennsylvania, and Nevada.  Whichever party wins two of these likely wins control (Dems need 50, GOP 51), assuming that each party holds in the other races.

Long shots: Tiffany Smiley in Washington and Joe O'Dea in Colorado are very good candidates in states where Democrats routinely win by 10–15 points.  In Iowa, Chuck Grassley's age may be hurting his chances to win one more term.  Ann Selzer's polls for the Des Moines Register are the most accurate pretty much every cycle.  Grassley is ahead by only 3, and below 50%, a dangerous position for an incumbent.  In Utah, Mike Lee is ahead but not by much over Evan McMullin, the candidate of NeverTrumps, a large group in the state.  If Republicans win one of their two challenges, or Democrats knock off Grassley or Lee, that party will be in good shape to hold Senate control.  McMullen claims to be an independent, but there is about a 100% chance he would vote for Schumer for majority leader.

One final comment: Do I believe that polls are accurate?  I certainly pay attention to polls, and some of them have much better track records than others.  Trafalgar was very good in Midwest states, not so good in Georgia.  CNN, CBS, NBC, and even Fox News have routinely been too favorable to Democrats.  Response to polls is well below 1%.  Some people, including political junkies, are probably anxious to be polled; others are paranoid about them.  In 2016, and 2020, there was a significant miss by many pollsters who underestimated Trump's support level.  Will this occur this year with Trump not on the ballot?  In 2018, the last midterms, polls proved more accurate.  I would argue that the country is more divided now than in 2018, with very low trust levels.  A lot of people are responsible for that.

Graphic credit: Nick Youngson, CC BY-SA 3.0, Pix4free.org.