Why is it taking this long to count ballots in some U.S. states?

Many states made it easier to request a mail-in ballot amid the coronavirus pandemic and concerns about crowded polling places. But they generally require more time to process than ballots cast in person.

States have different rules, and some ballots may not arrive in the mail for days

An election inspector looks at an absentee ballot as vote counting in the U.S. election continues in Atlanta. Several swings states have their own rules governing how they count mail-in ballots, which is causing delays in the results. (Brynn Anderson/The Associated Press)

Americans won't know the winner of the U.S. presidential election until well into Wednesday — if not beyond that.

The main reason? Many states made it easier for voters to request mail-in ballots amid the coronavirus pandemic and concerns about crowded polling places.

But mail-in ballots generally require more time to process than those cast in person.

And to top it off, states have different rules on how mail-in ballots can be counted.

In Canada, all federal elections are conducted by Elections Canada and operate under that agency. The U.S. does not have an equivalent, and it is up to each individual state to conduct the election and make their own rules. 

Here are some of the reasons why it's taking well past election night on Tuesday to see results in some states. 

In some states, mail-in ballots can't be counted until election day

Some states with extensive experience in using mail-in ballots have adjusted for those extra steps.

They allow the counting of ballots prior to election day, which makes a big difference in when the outcome is known.

In Florida, clerks can start counting ballots 22 days before an election. In North Carolina, county boards insert approved ballots into a voting machine beginning five weeks before the election, allowing for a prompt tabulation on election day.

But states such as Michigan, Pennsylvania and Wisconsin — all with Republican-led legislatures and all of them swing states — made a conscious decision to wait so there would be no counting of mail-in ballots prior to election day. 

Wisconsin and Michigan were nevertheless both called for Joe Biden Wednesday afternoon.

WATCH | Philadelphia rushes to count mail-in ballots:

Rush to count mail-in ballots underway in Philadelphia

3 years ago
Duration 0:40
A large vote-counting operation has been set up at the Philadelphia Convention Center to count mail-in ballots. Machines called extractors separate the ballot from the main envelope and the security envelope and then the ballots are scanned. They can scan 30,000 an hour.

The wrangling in the states over the use of mail-in ballots has come as U.S. President Donald Trump claims that mail voting is ripe for fraud.

Some ballots may not arrive for days

And here's another wrinkle that could delay the naming of a winner: In some key states, mail-in ballots can arrive several days after election day and still be counted, as long as they are postmarked by then.

Democrats have argued that the flood of absentee ballots and slow mail delivery in some areas make such a precaution necessary.

For example, mail-in ballots from Nevada voters are not due until Nov. 10 if postmarked by election day while in North Carolina, mail-in ballots aren't due until Nov. 12 if postmarked by election day.

Legal challenges ahead 

Pre-election day polling indicated that a majority of Trump's supporters had planned to cast their ballot on election day while more than half of Biden's backers had planned to vote by mail.

The Trump campaign has already announced legal actions challenging the validity of some ballots cast in key swing states.

The campaign said Wednesday it is suing to halt the vote count in Michigan and temporarily stop the vote count in Pennsylvania, claiming lack of "transparency."

WATCH | How the election unfolded:

How U.S. election night unfolded in 7 minutes

3 years ago
Duration 7:10
Watch highlights of our coverage of the U.S. presidential election.

With files from CBC News