(CNN) What's taking so long to determine which party has control of the US House and Senate? Blame California, Arizona, Nevada, Washington and the whole vote-by-mail West Coast, really.
Actually, don't blame them. This is just how elections work in 2022.
If elections weren't so close, it wouldn't take so long to figure out who won.
As of this writing, CNN has still not projected who will control either the House or the Senate in large part because of close races on the West Coast.
Read this more detailed report on the Thursday state of play from CNN's Jeremy Herb.
The two Senate races for which there is no projection are in Arizona and Nevada. There is no winner in Georgia's Senate race, but CNN has projected it will proceed to a runoff in December.
Here's a look at the 34 House races for which there is no projection as of this writing. You'll notice the western bias:
Two additional outstanding House races are in Alaska and Maine, where determining the winner in a ranked-choice voting system takes longer. Plus, there's one remaining House race in both New York and Maryland.
That means we know results for the vast majority of the elections that concluded Tuesday.
The benefit of knowing who won on Election Day is arguably outweighed by allowing more people access to the vote and the cost savings of not having to staff so many polling places.
Bill Gates, the chairman of the Maricopa County Board of Supervisors, told CNN's Sara Sidner on Thursday why it takes longer to count mail-in ballots and those placed in ballot drop boxes in the days immediately prior to and on Election Day. Maricopa is Arizona's most populous county that includes Phoenix.
With election officials visible, busily working behind him at the Maricopa County Tabulation and Election Center, Gates said those mail-in ballots that were dropped off right before and on Tuesday don't even start the important process of signature verification until the Wednesday after Election Day.
"We have experts here who go through, compare the signature on the outside of the ballot envelope with the signature that we have in our voter registration file," Gates said. "That takes a while because we got to get that right."
Most states have some sort of signature verification system for their absentee and mail-in ballots, according to a tally from the National Conference of State Legislatures.
"This is how we run elections in Arizona," Gates told Sidner. "If people don't like that, they can go to the legislature and have them pass new laws."
It's a process that's been in place in Maricopa County since the 1990s, he said. It's also overseen by both Republican and Democratic Party officials.
While Arizona still has a lot of in-person voting on Election Day, other states have moved to an entirely vote-by-mail system. The West Coast has been taking a long time to count these votes for years, but the process is getting added scrutiny this year because those unprojected races will determine who controls the chambers of Congress.
CNN's Eric Bradner talked to California's top election official back in 2018, when officials there were still counting ballots and it was not clear who would win a race more than three weeks after Election Day.
The official canvass isn't due for a month after Election Day in California because the state wants to be sure to count every vote.
Back in 2018, CNN projected that Democrats would take control of the House in the 11 p.m. ET hour on Election Day. This year, with Republicans on pace for only a very slim majority, it could still take days.
CNN's Gary Tuchman is in Las Vegas and did a good job Thursday explaining what's taking so long in Nevada, which transitioned to an all mail-in system in 2022.
Nevada ballots that were postmarked Tuesday can be received by election officials until Saturday and still be counted. It's not actually known how many ballots will trickle in because every registered voter in Nevada was mailed a ballot.
Tuchman pointed to data from Clark County, Nevada, officials: On Thursday, they were set to count more than 12,000 ballots that were delivered in the mail on Wednesday and nearly 57,000 ballots that were put in roughly 300 drop boxes on Election Day.
There were still thousands of ballots also streaming in to Nevada's second-largest county, Washoe, which includes Reno.
CNN estimates there are about 120,000 outstanding ballots in Nevada.
In Nevada, voters who made a technical mistake on their mail-in ballot will have the opportunity to "cure" it -- meaning correct it -- until November 15, a week after Election Day.
In Arizona, where the race for governor is particularly close, CNN estimates there are about 665,000 ballots still to be counted. Unlike in Nevada, where ballots that were postmarked by Tuesday are still streaming in, in Arizona, mail-in ballots must be received by election officials by 7 p.m. on Election Day.
Officials processing those hundreds of thousands of mail-in and absentee votes that arrived Monday and Election Day originally wanted to have them almost entirely counted by Friday or Saturday, according to Sidner, but Gates told her, "I think we'll see the lion's share here wrap up early next week."
The additional issue in Maricopa County is around 17,000 in-person Election Day ballots that would not go through tabulators at polling locations because of a printing error. Those are also being counted.
Meantime, look for periodic evening dumps of additional votes that could change the momentum of these extremely tight races.
If the races were not so close, there might not be enough of these mail-in ballots to make a difference in the final tally. News organizations won't project a winner unless there is a certainty of victory.
It used to take a year to seat a new Congress.
So many congressmen-elect died between Election Day 1930 and the beginning of the next Congress (14 members-elect died!) that ensuing special elections changed the balance of power before the new Congress started in 1931.
One of the elected members who died was then-House Speaker Nicholas Longworth, otherwise known as husband of former President Theodore Roosevelt's socialite daughter, Alice.
Longworth was expected to be speaker again, but after his death from pneumonia, Republicans lost control as special elections were held to fill the 14 vacancies. Ultimately, it was Democrat John Nance Garner who took the speakership. Democrats would keep control, with a few two-year hiccups, until 1994. Garner went on to be President Franklin D. Roosevelt's first vice president two years after becoming speaker.