Hi. Welcome to On Politics, your guide to the day in national politics. I’m Lisa Lerer, your host.[Get On Politics delivered to your inbox.]He’s running!Julián Castro, the former housing secretary and former mayor of San Antonio, Tex., said on Saturday that he will run for president. The first major Latino candidate to make a 2020 bid, Mr. Castro, 44, advocated for a fairly progressive platform in his announcement speech.Here at On Politics, we’re trying to talk to all the 2020 candidates as they enter the race, and Mr. Castro agreed to be our first subject. We spoke late Sunday afternoon, shortly after he landed in San Juan, Puerto Rico, where he planed to speak to a group of political activists and tour a hurricane recovery zone. (As usual, our conversation has been condensed for clarity.)Lisa: Hi. Thanks for chatting with us. As you well know, you’re one of the first of what’s likely to be quite a number of Democrats running for president. How can you distinguish yourself?Castro: I have a track record of getting things done as mayor of San Antonio and as secretary of housing. I have a strong vision for the country’s future. And I’ve lived a life that I believe lets me understand people all along the scale of experience in our country. I had a modest upbringing and I can understand people that are striving to reach their dreams. I’ve also reached my dreams and can understand folks who have had a lot of success.You’re in Puerto Rico right now. That’s pretty far from Iowa. Why start your campaign there?I want everybody to understand that everybody counts in this country. The most basic tenet of government is protection. And this administration failed our fellow Americans in Puerto Rico by not protecting them after Hurricane Maria. I’m going to highlight that, and then we’ll let folks know that in the years to come everybody is going to count in this country, including the people of Puerto Rico.President Trump has said there’s a massive crisis on the border. Do you agree?Not at all. The crisis that exists is a crisis of leadership. This president has failed. He promised all of us that if Americans could just be cruel enough to separate babies from their parents at the border, that it would deter more families from coming over there. Now we’ve seen that more families are coming over. So he has failed with his policies, and he’s failed in trying to convince the American people that he’s not to blame for this shutdown. And the best thing that he can do now is to set aside his political ploy of the wall.You may be the only Latino in a crowded race. How do you think that will impact the contest?I’ve got to be myself, and I’m confident that I can appeal to a broad cross-section of Americans. At the same time, of course, there’s significance to the Latino community because I believe a lot of Latinos feel targeted right now by this administration. For me, personally, I can relate to many of today’s immigrants because my grandmother that I grew up with came over from Mexico, and I grew up in San Antonio, just a few hours away from the border. So I’ve seen the positive value that immigrants add to this country in a very direct way. And I know that these cities along the border are some of the safest cities in the United States.Any Democrats who runs will have to answer the question of how to challenge Mr. Trump. What’s your philosophy?The way I see it is that, above all else, people want to know what you stand for. I’m going to give people a strong positive vision for our country’s future. Of course, I’m going to point out where I differ with the president. But my first priority is to let you know, if you elect me, what I’m going to do for you or for your family.Do you think a Democrat will end up running against Mr. Trump? Like, do you think he’ll still be in office next year? That’s probably the best question out there now. You know, it’s hard to tell what’s going to happen. My hope is that these investigations will proceed thoroughly and Congress will act once the investigation is finished appropriately. So right now, I’m prepared to face President Trump in November of 2020. If there’s somebody else who’s up for the Republicans, then I’ll face them.Mr. Trump is known for giving nicknames to his opponents. What do you think yours will be? Who knows and who cares. You know, the thing about magic tricks is that even magic tricks get old. And his tricks are getting old.[Sign up here to get On Politics in your inbox.]____________________A T.S.A. family, hit by the shutdownTalks between the White House and congressional Democrats to end the longest government shutdown in history remained stalled on Monday. That’s more bad news for government employees, who don’t know when they’ll get their next paycheck.Last week we spoke to Júlia Quintanilla, a contract janitor at the Department of Agriculture, who was worried about buying groceries. Today, we’re bringing you the story of T.S.A. agents Daniel and Jennifer Young. The couple met on the job at Huntsville Municipal Airport in Alabama, where they’ve both worked for over a decade. They stagger their shifts, with Ms. Young leaving the house around 3:30 a.m., so they can care for their 5-year-old twin daughters.Deemed essential for national security, T.S.A. agents are required to work during the shutdown. But they’re not getting paid. Many live paycheck to paycheck, making an average salary of $35,000, according to officials at the American Federation of Government Employees.High numbers are calling in sick and resigning, a situation that’s forced airports in Miami, Houston and Washington to close some screening lines. And on Sunday night, the T.S.A. confirmed that a passenger with a gun passed through a checkpoint in the Atlanta airport and flew to Tokyo. The agency denied any connection with the shutdown, but the incident sparked speculation.To ease some of the stress, David P. Pekoske, the T.S.A. administrator, announced that employees would receive a day’s pay if they worked Dec. 22 and that uniformed officers will get a $500 bonus on Tuesday.So far, the Youngs have been able to stretch their finances to cover their expenses. But if the shutdown continues into next month, the couple said they will have to make some “really hard choices” about which bills to pay.“We had a screw in our tire, and I had to go and figure out how we’re going to pay for it to get fixed,” said Mr. Young, 36, a Marine Corps veteran. “That increases your stress level. You can’t stop life when you’re not getting paid. You still have to go to work.”“I can’t pay my electric bill with an i.o.u. I can’t pay my mortgage with an i.o.u.,” Mr. Young added. “All my decisions are based on the fact that I have no idea when I’m going to get paid or how I’m paying for this. I will be pretty much living off credit cards in February.”“Kids sense a lot,” said Ms. Young, 34, “but I feel like they don’t need to know. It’s my job to take care of them. It’s my job to provide for them. Even if I have to make tough choices. At least there’s food in their bellies.”Have you been personally affected by the shutdown? Tell us about it: OnPolitics@nytimes.com. Our inbox is always open!____________________What to read tonight• More than 30,000 Los Angeles public-school teachers began a long-planned strike on Monday, the first in three decades in the nation’s second-largest school district. Times reporters are following the story live here.• “Portraits of these women of the 116th Congress are a testament to what power looks like in 2019 — and the possibilities of what it may look like in the years to come.” A pretty fascinating photo spread on the women of the new Congress.• Give up on “inbox zero.” In 2019, embrace inbox infinity. (Sorry if I don’t reply to your message.)____________________… SeriouslyThe most controversial 2020 platform? Embracing carbs.Also, you know what will crush all these diets? Iowa. (In 2012, I tried fried butter drizzled with some kind of icing at the Iowa state fair. That was a real product being sold. And, dear reader, it wasn’t half bad.)_____________________Megaphone illustration by Tim Lahan.Were you forwarded this newsletter? Subscribe here to get it delivered to your inbox.Thanks for reading. Politics is more than what goes on inside the White House. On Politics brings you the people, issues and ideas reshaping our world.Is there anything you think we’re missing? Anything you want to see more of? We’d love to hear from you. Email us at firstname.lastname@example.org.