Confirming weeks of speculation, former U.S. representative Beto O’Rourke of El Paso on Thursday became the fifteenth Democrat to announce that he’s running for president in 2020. He vowed to directly challenge Donald Trump on the president’s signature issue: immigration and border security. Yet he continued to offer few details of the specific policies he would pursue.

O’Rourke announced his presidential candidacy Thursday morning in a video to supporters. The day before, he talked about his campaign plans with Texas Monthly as he drove to El Paso International Airport en route to Iowa, where the first votes of the 2020 nomination contest will be cast next February 3. He had spent the morning with his wife, Amy, and dropped off their three children at school—likely their last taste of family normalcy for months or years.

I am running to serve you as the next president. The challenges we face are the greatest in living memory. No one person can meet them on their own. Only this country can do that, and only if we build a movement that includes all of us. Say you're in: https://t.co/EKLdkVET2u pic.twitter.com/lainXyvG2n — Beto O'Rourke (@BetoORourke) March 14, 2019

“Our democracy has never been under attack like it is now, both from foreign actors like the government of Russia, and then also from within, [with] the highest levels of partisanship that we’ve seen—and a president who is undermining every important democratic institution in this country,” O’Rourke told us. “So we have never been tested like we are at this moment.” In response, he promised to lead “the largest grassroots effort in American history, following the largest grassroots effort in Texas history.”

O’Rourke is the second Texan to join the Democratic presidential race, following Julián Castro, who has served as mayor of San Antonio and secretary of the U.S. Department of Housing and Urban Development.

The 46-year-old O’Rourke was largely unknown outside his hometown when he announced in 2017 that he would challenge Republican U.S. senator Ted Cruz of Texas. O’Rourke was then serving his third term in the U.S. House of Representatives, a tenure entirely spent in the minority party, limiting his opportunity to make much of a legislative mark. On the day he announced, Texas’s other senator, John Cornyn, said O’Rourke was on a “suicide mission.” But through deft use of social media, O’Rourke built a large following in Texas and elsewhere. He would raise a record-shattering $80 million, including more than $36 million from donors contributing less than $200.

O’Rourke lost to Cruz by 2.5 percentage points, the closest a Democrat has come to winning a statewide race in Texas in more than twenty years. Texas turnout was up 80 percent over the 2014 midterm election, and O’Rourke was credited with helping down-ballot Democrats win congressional, legislative, and judicial races. After losing to Cruz, he began mulling a presidential bid.

True to the form he established in his Senate run, O’Rourke’s life continued to play out on social media as he pondered his future. He blogged about road trips as he made up his mind, saying at one point he was “in and out of a funk.”

But in recent weeks—particularly after President Trump held a campaign rally in O’Rourke’s hometown on February 11—it became increasingly evident that he would run for president. O’Rourke said a community-organized march and rally held simultaneously with the president’s event played a key role in pushing him to run for president.

During his Senate campaign, O’Rourke said his experience representing a key stretch of the U.S.-Mexico border uniquely positioned him to lead the state. He’s making a similar argument in his presidential campaign. “At a moment where the president has fully trained the focus of this country on us . . ., we’re ready to share a profoundly positive story about what we contribute to the greatness of this country,” he said.

Despite his emphasis on his border roots, O’Rourke has struggled to articulate specific policies he would propose on immigration and border security, particularly in a January interview with the Washington Post. In his interview with Texas Monthly, O’Rourke said he would reframe the immigration debate “with the truth and the facts and remind people where we are—a country of immigrants and asylum seekers and refugees from the world over, immigrants and asylum seekers who are part of our success.”

Trump has, of course, made curbing immigration a focal point of his 2016 campaign. His administration implemented policies that led to thousands of migrant children being taken from their parents at the border and thousands more children being detained for months in a tent facility in El Paso County. Trump forced a 35-day government shutdown in an ultimately unsuccessful effort to bend Congress to his will on border wall funding. He then declared a national emergency so he could redirect government funds to build more barriers on the border. The House has already voted to rebuke that declaration, and the Senate is expected to pass the measure as early as today.

O’Rourke and others have long accused Trump of falsely portraying the border situation to whip up fear. Trump’s critics point to government statistics that show border apprehensions at historic lows in the years leading up to his presidency. Apprehensions of illegal migrants have risen dramatically in recent months, mostly among Central American families and unaccompanied children who enter the United States, seek out Border Patrol agents, surrender, and request asylum because they say they are fleeing poverty and violence at home.

“El Paso is one of the safest cities in the country,” O’Rourke said, “and if our safety is in part predicated upon the fact that we are a city of immigrants, then it should motivate us to rewrite our immigration laws based on our experiences and our values. We should ensure that no one who is attempting to lawfully enter the United States is waiting in a line that stretches twenty years long. We should significantly lift the visa caps that we have right now, acknowledge the importance of family unification, acknowledge the importance of those who want to work at jobs in this country for which we can find no one born in this country willing to work. We should acknowledge that we have laws and international obligations, that we honor those obligations.”

Trump and other Republicans are increasingly accusing Democrats of drifting into socialism through policy proposals such as Medicare for All, free college, and the Green New Deal. O’Rourke rejected that characterization while also positioning himself as a candidate who could win over a broad array of voters.

“I think the people of this country understand the historic challenges that we face [and] that it’s going to take very bold leadership. It’s going to take a renewal of service and, yes, sacrifice.” He argued for “every single American to be able to see a doctor to be well enough to live to their full potential . . . What I have found traveling Texas and listening to people in other parts of the country is that is a very common aspiration. And it cannot just be Democrats who do this. It’s going to have to be all of us. And that means that you look for the common ground, enlarge it where you can, and then work together to get that done.”

The Democratic presidential field has drawn more women and people of color than any primary race in history, reflecting the growing role those groups play in the party. “You have one of the most diverse, one of the smartest, one of the most exciting group of contenders that we have ever seen, any one of whom would be far better than President Trump,” O’Rourke said. What separates him from the field, he added, is his experience in government and business and the surprisingly close race he ran in 2018. Even though he lost, he said, that campaign “really became part of a larger movement, the power which still exists in some of the people that you saw win elections, whether it was the seventeen African American women in Harris County who won judicial positions or all of those who were part of our campaign who are now running for office, engaged for the first time. A state that saw a nearly five-hundred-percent increase in young voter turnout.”

O’Rourke said he has an “ability to unify people” and an ability to compete in Republican states like Texas. “I don’t know that there’s another candidate who can do that,” he said.

In his race against Cruz, O’Rourke took an upbeat approach and for much of the campaign didn’t attack his opponent directly. As Election Day drew closer, many of his supporters urged O’Rourke to go on the attack against Cruz. He did so in their second debate, repeating Trump’s “Lying Ted” sobriquet for Texas’s junior senator. But O’Rourke soon expressed regret for doing so. In the 2020 primaries, many Democratic voters will be looking for someone tough enough to stand toe-to-toe with Trump, who revels in name-calling and often eschews facts.

“You can be tough for people—fighting for them and relentless in pursuit of the solutions—without demeaning others or becoming petty,” O’Rourke said.

In publicly weighing whether to run for president, O’Rourke frequently mentioned concern about the toll a presidential campaign would take on his wife, Amy, and their three children—Ulysses, twelve; Henry, ten; and Molly, eight.

“We’re going to give it our all, and that means some sacrifice from everyone,” he said, “but we are very mindful of how many thousands of families in El Paso and at Fort Bliss are sacrificing right now with loved ones deployed across the world and in harm’s way. We can all do our part.”

Throughout his interview, O’Rourke sought to embrace issues important to Democratic primary voters while also eyeing the 2020 general election. In stressing the need for action on climate change, for example, he said, “That’s not an ideological issue or challenge. That’s a challenge for our entire democracy. And it means that all of us have to come together. But I think in order to do that, we have to make sure that we don’t write anybody off who doesn’t share our party affiliation or our views on every single one of these issues, because it really is going to take all of us.”