Why Trump hates mail-in voting

[U.S. President Donald Trump, saying:] "When you do all mail-in voting, ballots, you're asking for fraud.”

President Trump has long-sought to discredit mail-in voting, portraying it as a system rife with fraud.

[U.S. President Donald Trump, saying:] “People steal them out of mailboxes. People print them and then they sign them and they give them in and the people don't even know or they're double-counted.”

But it’s been used for decades, with little evidence of any significant problems.

In fact, it formed nearly a quarter of voters in the 2016 election.

And with public health fears, the number of absentee votes is expected to almost double on November 3.

[U.S. President Donald Trump, saying:] "This will be, in my opinion, the most corrupt election in the history of our country."

Election experts disagree.

They say it would be nearly impossible for an election to be disrupted by fake mail ballots.

Why? Well, for one thing there can be hundreds of different ballot designs in a single county alone.

That's because voters aren't just voting for president, they're voting for the local mayor, town council, sheriff's office, etc.

So the ballot for one district will be different than their neighbor.

And there are over 3,000 counties in the United States.

These are printed on a specific type of paper with technical markings.

States also require voters to sign the outside of the envelope, which is matched to a signature on file.

As such, documented cases of fraud are very rare.

Take Oregon for example, where over 15 million mail-in ballots have been cast since 1998.

Out of that, only 14 fraud cases were ever found, that's according to the conservative think tank, the Heritage Foundation.

Fraud aside, there are drawbacks though.

1% of mail ballots were rejected in 2016 for arriving too late, or missing signatures.

They can pose disability and linguistic barriers.

And delivery can be problematic where residents lack street addresses, such as on on Native American reservations.

But it can minimize the risk of long lines, faulty voting machines and staff shortages.

Turnouts also tend to be higher in states that conduct elections by mail.

So if fraud is rare -- and it boosts voter turnout -- why do Trump and Republican allies take such issue with it?

Trump has even himself submitted absentee ballots through the mail.

[U.S. President Donald Trump, saying:] "The Democrats are also trying to rig the election by sending out tens of millions of mail-in ballots ..."

Republicans worry that easier voting will hurt their party's election chances.

They say an increase in the ease and numbers of mail ballots would favor Democrats,

who are confident that more ballots counted would translate into more election victories.

[Representative Alexandria Ocasio-Cortez, saying:] "We do not have mail-in ballots, we do not have same-day registration. And these are all enormous obstacles to the vote..."

Democrats are therefore pushing to expand vote-by-mail options.

Roughly one third of states currently require a valid excuse for a mail vote.

Thirty allow it on request, and five states send ballots to all voters automatically.