Beware of the Blue Shift, followed by the Red Mirage — flaws in the U.S. electoral system, if you will — that will ultimately decide the 2020 presidential election.

Never heard of them? Julian Castro breaks it down in a rather concise video produced by Now This. 

The Blue Shift is a phenomenon in elections, where in-person votes are counted first by Republicans, and highly Democratic mail or provisional votes are counted later. 

Imagine it's the night of November 3rd, and President Trump, with a slim lead in one or two key states like Florida or Pennsylvania, declares a premature victory despite the omission of tens of thousands of uncounted votes, including those provisional and mail-in votes. 

Here comes the Blue Shift, sweeping up the election results in the days after these votes are counted. Trump's lead decreases, resulting in a clear path to a Biden-Harris victory. 

That would be a peaceful scenario. But Trump will probably want to stick with the incomplete results of November 3.

"Two things," Castro says. "Don't expect to know who's going to win on November 3rd. And if Donald Trump is going to steal this election, he'll probably start with the Blue Shift.

The COVID-19 pandemic has made it clear that this election cycle will be slow in terms of counting votes, so any declaration of early victory on Election Day must be scrutinized.

Castro says there are some reasons why Democratic votes are counted later in the process, and the first is a population issue. He uses Florida to explain this. 

"Liberty, a bright red county in Florida, has about 8,400 people. Broward, a dark blue county, has almost 2 million. Which one do you think will finish counting first?"

Reason number two refers to mail ballots. Castro points out that many states won't start counting mail ballots until November 3, and those ballots are counted after the in-person votes are processed.

"The mail ballots have to be opened, their signatures verified and then counted. It takes time," Castro said. "As to why these votes tend to be blue, it's also quite simple. Historically, Democrats have been more likely to vote by mail. And in 2020, that is expected to be even more true, but who can guess why?

Here, Castro is referring to the sabotage of the U.S. Postal Service. Under the direction of Postmaster DeJoy - a plant of the Trump administration - the USPS has experienced cutbacks that have resulted in serious delays in the mail. This occurs during an election cycle in which a record number of voters will be voting by mail or voting early. 

Combine this with Trump's efforts to stop the count on November 3, and the voter suppression tactics of his supporters as seen in Texas under the Abbott administration, and it makes a lot of sense why the GOP will declare early victory and then challenge the vote during "Blue Shift.

"This just happened in 2018. Broward County in Florida was still counting the ballots after Election Day and the Republican running for the Senate, then-Governor Rick Scott, made it sound like a fraud," Castro continued.

Although official investigations into the 2018 Florida election came back later saying there was nothing fraudulent, Trump at the time tweeted 10 times, complaining or spreading conspiracy theories about a rigged election. 

Trump is aware of the "Blue Shift" phenomenon, and is likely to use it to his advantage, similar to how Rick Scott did. But of course, Trump has more power, so he will try to extend the life of the "Red Mirage" as much as he can. 

"On election night, there is a real possibility that the data will show the Republicans leading before all the votes are counted. They could pretend that something sinister is happening when the count changes in favor of the Democrats," Castro continued.

This is already happening, even though it is acknowledged that this year will have an election "season" rather than a single election "day" due to the unprecedented number of mail ballots in the middle of COVID-19.

Trump has said that the courts should prevent ballots from being counted after November 3. 

Pennsylvania recently approved a three-day extension for counting mail ballots, which Trump called a "disaster for our nation," and that "Democrats are trying to steal this election.

Castro even said that some GOP members refer to Election Day as "game day," "as if legal votes counted later should not be counted.

The danger lies in a declaration of victory by Trump before all the votes are counted, following the argument that the late-counted votes are fraudulent, launching a legal fight in the swing states. 

This could well happen in Pennsylvania, the nation's largest battleground state. Pennsylvania is one of those states that won't start counting absentee ballots until November 3.

"Could I win in court?" Castro asks. "It doesn't really matter. They could delay things long enough for the vote recount and certification deadlines to expire, and then argue that the recounts should be stopped. Not like Florida in the 2000 election.

It's as if the Trump Administration has been planning this from day one. These challenges, should they occur, will be heard by a judiciary that Trump and Senate Majority Leader Mitch McConnell have put a lot of effort into packing with conservative judges. 

To this, Castro serves his call to action.

The first line of defense is to know about 'Blue Shift,' and to insist that we count every single vote.