'Start Here': Transgender memo, caravan. What you need to know to start your day.

It's Tuesday, Oct. 23, 2018. Thanks for choosing to start here.

1. Trump calls US-bound migrant caravan a 'national emergency'

President Donald Trump has called the caravan of thousands of migrants from Central America a "national emergency" and vowed to send the military to the U.S.-Mexico border.

He asserted yesterday on Twitter, without evidence, that violent criminals and Middle Eastern people were among the marchers.

ABC News Chief National Correspondent Matt Gutman, who's traveling with the caravan, tells us he saw no evidence to support the president's claim.

Gutman says of the growing humanitarian crisis and the treacherous 1,500-mile journey for the asylum-seekers: "They've done about 40 miles in two days, but they are footsore and exhausted, and the heat is absolutely debilitating."

2. Clinton, Biden stump for Democrats in Florida

The midterms are two weeks from today, and both parties are furiously campaigning in a handful of close races.

In Florida, Democrats are trying to take the governor's mansion for the first time in nearly two decades, and Republicans are aiming to take back a Senate seat.

Two key groups candidates are keeping an eye on in these races are young voters and Puerto Rican voters who moved to Florida after Hurricane Maria.

ABC News Chief National Correspondent and Floridian Tom Llamas tells us: "A lot of people are wondering about the youth vote in Florida because of Parkland and how engaged all those student survivors became in the days, weeks and months leading up to the midterms because of what happened inside their school."

3. Trump defends Saudi arms deal, inflates jobs created

Trump continues to champion the $110 billion arms deal with Saudi Arabia in the wake of Washington Post writer Jamal Khashoggi's death. He told reporters on Monday: "I don't want to lose all of that investment that they have made in our country. I don't want to lose a million jobs."

But the president is inflating the number of jobs gained in the deal, according to ABC News' Luis Martinez, who covers the Pentagon.

4. Report: Trump administration weighs change to gender definition

The Trump administration is reportedly weighing whether to officially define gender as biological, according to the New York Times, which would roll back federal protections for the transgender community.

The hashtag #WontBeErased went viral on social media after the report, sparking protests in favor of transgender rights around the country on Monday.

"The trans community has completely mobilized in the last 30 hours," "Nightline" co-anchor Juju Chang tells us, "and there are those who say that they're going to fight to do whatever they can to reverse this."

Health and Human Services Department spokeswoman Caitlin Oakley called the Times report "misleading," and insisted the "HHS's Office for Civil Rights will continue to vigorously enforce all laws as written and passed by Congress, prohibiting discrimination in healthcare on the basis of race, color, religion, national origin, sex, age and disability."

5. Moving money from zero-interest deposits to higher-yield alternatives

As the Federal Reserve has raised interest rates over the last few years, banking customers are beginning to move their money from non-interest-bearing deposits into higher-yield savings accounts.

Banks profit by taking in deposits and lending out money, making more on the interest that's lent than what they're paying to customers. Because customers are pulling their money out of accounts that don't earn interest, the four largest U.S. banks are reporting a 5 percent drop in deposits compared to last year, the first decline for those accounts since before the financial crisis, according to the Wall Street Journal.

ABC News Chief Business and Economics Correspondent Rebecca Jarvis breaks down what's happening: "We've been conditioned to essentially accept the fact that leaving our money in the bank isn't going to make us money."

Other news:

'The president of the United States says it's OK to grab women by their private parts': A man arrested in New Mexico stands accused of grabbing a woman's breast during a flight.

'They spun the wheel of discrimination and landed on transgender': Stephen Colbert slams the Trump administration's consideration of anti-transgender biological definitions.

'The middle class will see straight through this scam': The president is roundly criticized for floating the idea of a middle-class tax cut that can't possibly be voted on before the midterms.

'When I told him that I would not lie after he sexually harassed her, he told me that if I didn't, him and the others couldn't work with me': A whistleblower describes being forced out of a senior-level TSA job for confronting superiors about their bullying of female colleagues.

'There's a clear symbolic value of being the world's longest bridge': A $20 billion bridge connecting Macau to Hong Kong is finally set to open.

From our partners at FiveThirtyEight:

Governors Update: Democrats Suddenly Have A Real Chance In Alaska

Last 'Nightline':

Thousands endure brutal conditions in migrant caravan bound for US border: ABC's Matt Gutman reports on the desperate circumstances these migrants face on their journey through Mexico and on the political backlash.

Beto O'Rourke, Ted Cruz battle in heated Texas Senate race: ABC's Paula Faris sits down with the two candidates in one of the most consequential midterm races.

On this day in history:

Oct. 23, 1973 -- Richard Nixon agrees to turn over White House tape recordings to Judge John Sirica.

Today's must-see photo:

LGBT activists from the National Center for Transgender Equality, partner organizations and their supporters hold a 'We Will Not Be Erased' rally in front of the White House, Oct. 22, 2018, in Washington. (photo credit: Chip Somodevilla/Getty Images)

For more great photos from around the world click HERE.

What's hot on social:

A shark out for blood may have taken a bite out of an Australian surfer over the weekend, but it didn't damage the man's spirit. The surfer says he head-butted the shark.

All right, you're off and running. You can always get the latest news on ABCNews.com and on the ABC News app. Details on how to subscribe to the "Start Here" podcast are below. See you tomorrow!

"Start Here" is the flagship daily news podcast from ABC News -- a straightforward look at the day's top stories in 20 minutes. Listen for free every weekday on Apple Podcasts, Google Podcasts, iHeartRadio, Spotify, Stitcher, TuneIn, or the ABC News app. On Amazon Echo, ask Alexa to "Play 'Start Here'" or add the "Start Here" skill to your Flash Briefing. Follow @StartHereABC on Twitter, Facebook and Instagram for exclusive content, show updates and more.